Tag Archives: cop

Technical requirements for safety in metal scaffolding – Tubular Scaffolds

Leave a reply

Technical requirements for safety in metal scaffolding – Tubular Scaffolds

5.2  Tubular Scaffolds

They  are  constructed  in  tubes  and  couplers  for  the  purpose  of  providing working platforms. Each scaffold should be constructed in accordance with the design and drawings of professional engineer. Recommendations for the design, construction and use of various types of scaffolds can be found in BS EN 12811 or  other  equivalent  national/international  standards  or  provisions. All  tubes, couplers and fittings should  comply  with  BS 1139,  BS  EN  39,  BS  EN  74, BS EN 1004 and BS EN 12810 or other equivalent national/international standards or provisions. When other tubes or materials are used, structural calculations should be carried out using the properties of the tubes or materials used and the structures assembled so that equal or even higher safety standards than the aforesaid standards can be achieved. In order to calculate the height of a tubular scaffold, the table in Section 5.1.1(i) and the following table should be made reference to:

 

Duty Max. number of platforms Commonly used widths

using 225mm boards

 Max. bay length (m)
Inspection and very light duty 1 working platform 3 boards 2.7
Light duty 2 working platforms 4 boards 2.4
General purpose 2 working platforms

+ 1 at very light duty

 5 boards or

4 boards + 1 inside

 2.1
Heavy duty 2 working platforms

+ 1 at very light duty

 5 boards or

5 boards + 1 inside or

4 boards + 1 inside

 2.0
Masonry or special duty 1 working platform

+ 1 at very light duty

 6 to 8 boards 1.8
Note:   (a)   The boards are timber scaffold boards of nominal cross sections

38mm x 225mm. Decking units of other types or dimensions but with equal or greater strength can also be used.

 

(b)    The  normal  lift  height  for  works  such  as  brickwork  is  1.35m, and for walk-through scaffolds is 2.0m. For greater lift height or different loading conditions, reference should be made to the design criteria in BS EN 12811 or other equivalent national/ international standards or provisions.

The  following  subsections  highlight  some  essential  safety  requirements  for some special types of tubular scaffolds made of steel. A tube made of steel should  have  a  yield  stress  not  less  than  235N/mm2,  and  should  have  an outside diameter of 48.3mm and a wall thickness of 4mm.

5.2.1  Independent tied metal scaffold

It   should   consist   of   a   double-row   of   standards   with   each   row parallel to the building (See Figure 1 for details). The inner row should be set as close to the facade of the building/structure as is practicable. The distance between the lines of standards should be the minimum necessary   to   accommodate   the   required   boards   and   toe-boards forming a working platform. The standards should be connected with ledgers  parallel  to  the  building/structure  and  fixed  with  right  angle couplers and with transoms fixed to the ledgers with putlog couplers to give the required platform widths.

(a)      Standards

(i)      The joints in standards should be staggered. Joints in standards of scaffolds tied to a building/structure should be made with either joint pins or sleeve couplers.

(ii)     For scaffold that is free standing or projecting above the level of a building/structure or otherwise subject to forces that would produce tension in the standards, the standards should be joined in manner capable of resisting the applied tension.

(iii)    No  more  than  three  out  of  the  four  standards  at  the  corner  of any  bay should have joints  in  the  same  lift  except  in  the  case of the bottom 6.5m of a scaffold where an extended base lift is necessary for pedestrian access or other reason.

(iv)    Where  any  of  the  standards  in  a  scaffold  are  at  a  level  lower than the remainder of the standards, the extension downwards should be stiffened by horizontal tubes, in two directions at right angles and fixed at lift heights (i.e. the vertical intervals at which standards are linked to one another).

(v)     Where  access  for  the  public  is  required  under  the  first  lift,  a height of up to 2.7m is permissible, provided that the load in the standards does not exceed the maximum permissible axial stresses and loads for the steel scaffold tubes.

(b)      Ledgers

(i)      Ledgers    should    be    fixed    to    standards    with    right    angle couplers  and  should  be  horizontal  except  that  a  foot  lift  may follow the slope of the ground at the base of a scaffold. For this situation, the transoms should be attached to the standards and the ledgers to the transoms.

(ii)     Joints  in  ledgers  should  be  made  with  sleeve  couplers  or expanding joint pins. Joints  in  ledgers  on  the  same  lift  and  in adjacent lifts should not normally occur in the same bay.

(iii)    When   guard-rails   are   to   remain   permanently   in   place,   the absence of a joint in the guard-rail in any bay may be accepted as giving sufficient continuity to the scaffold to permit joints in the ledgers above and below it in the same bay.

(iv)    Where  joints  are  required,  they  should  be  positioned  at  a distance not greater than 1/3 of the span between adjacent standards.

(v)     In  the  case  of  curved  scaffolds,  fittings  other  than  right  angle couplers may be used to join the ledgers to the standards provided that they are of adequate strength or otherwise supplemented by a right angle check coupler. Besides, for large radius curves, separate scaffolds with platforms of the same height may be used.

(c)      Transoms/putlogs

(i)     The  length  of  transoms/putlogs  should  vary  according  to  the intended use of the scaffold.

(ii)    Transoms   should   be   extended   inwards   and   outwards   for the purpose of butting the face of the building and fixing the longitudinal bracing.

(iii)   Transoms should be fixed to the inside and outside ledgers with right

angle or putlog couplers.

(iv)    Boarded lifts: The spacing of transoms/putlogs for boarded lifts should be in accordance with the followings:

 

Nominal

Thickness

of Board (mm)

 Max. Span between Transoms/ Putlogs (m) Min. Overhang

(mm)

 Max. Overhang

(mm)
38 1.5 50 150
50 2.6 50 150
63 3.25 50 150

(v)    Non-boarded  lifts:  Transoms/putlogs  for  non-boarded  lifts  should be  fixed  at  one  per  pair  of  standards,  including  the  pair  at each  end  of  the  scaffold,  and  should  be  fixed  within  300mm of the standard. On scaffolds of a height more than 50m, the transoms on unboarded lifts, when fixed at the frequency of one transom per pair of standards, should be fixed to the ledgers or standards  with  right  angle  or  other  suitable  couplers  provided they are capable of sustaining a safe working slip load of 5kN.

(d)      Working platform

Safety requirements for a working platform are the same as described in

Section 5.1.4. Other requirements are as follows:

(i)     Any group of boards across the width of the scaffold should be of the

same length, with all boards of the same thickness.

(ii)     The spacing of the transoms to support the boards should vary according to the thickness and length of the boards as specified in Section 5.2.1 (c)(iv).

(iii)    The ends of a working platform should extend beyond the end of the wall or working face by a distance of 600mm when work is to be carried out up to the end of the wall.

(iv)    Gangways and working platforms should preferably be horizontal but may slope at an inclination of up to 1 vertical to 4 horizontal without stepping laths. At slopes steeper than this they should be provided with stepping laths to provide a firm foothold.

(v)     Ladders  or  other  suitable  means  should  be  provided  so  as  to enable workers to gain access to and egress from one platform to another.

(e)      Stair/ladder access to and in scaffolds

Stair and ladder towers should be constructed with one side common with the outside of the scaffold. Bracings should be fixed to the remaining sides except in the bays through which access and egress is required. The superimposed loading adopted in calculations should be not less than

2kN/m2   for all landings and stairs in stair towers and ladder towers.

(i)      Every sloping ladder should stand on a firm and level base and be supported only by the stiles. The stiles should be securely fixed to the scaffold by lashings or by other attachments at the top.

(ii)    Ladder should be set at an angle of 4 vertical to 1 horizontal.

(iii)    Ladders should project at least 1.05m above the top landing with the landing rung level with or slightly above the level of the landing. Ladders should not be extended by lashing two lengths together.

(iv)    The vertical distance between two successive landings should not exceed 9m. The landings should be provided with access holes for the user which should not exceed 500mm in width and should be as small as practicable in the other direction.

(v)     Where practicable, the ladder access to the scaffold should be with its own ladder tower fixed to the outside of the main scaffold.

(vi)    Both ladder towers and stair towers should be fully decked at the landings. Toe-boards should be provided at the landings.

(vii)  Every landing and every side of a stair shall be provided with suitable guard-rails of adequate strength. The height of a top guard-rail shall be between 900mm and 1 150mm. The height of an intermediate guard-rail shall be between 450mm and 600mm. (Third Schedule to the CSSR)

(viii)  The gaps in the decking to allow access and egress from lift to lift up the ladder or steps should be as small as practicable. Short boards necessary to complete the decking round the access hole should be tied down and supported at the correct centres.

(ix)    Every  gangway  or  run  in  the  scaffold  shall  either  be  closely boarded, planked or plated, or is a platform consisting of open metal work having interstices none of which exceeds 4 000mm2  in area. (Third Schedule to the CSSR)

(x)     Every side of the gangway or run shall be provided with suitable guard-rails of adequate strength. The height of a top guard-rail shall be between 900mm and 1 150mm. The height of an intermediate guard-rail shall be between 450mm and 600mm. (Third Schedule to the CSSR)

(f)       Ties

(i)      When a working lift (i.e. the assembly of ledgers and transoms forming a horizontal level of a scaffold) is required at 2m height and no firm part of the building/structure has been constructed to attach a tie, scaffold should be temporarily stabilized by raking tubes or other means. Such tubes should also be fixed during dismantling if low level ties are impracticable.

(ii)     In   the   situation   where   ties   may   be   temporarily   removed, they  should  be  maintained  at  such  a  frequency  that  there  is always one for every 25m2   of scaffold area and they should be reasonably evenly distributed over the scaffold surface, both horizontally and vertically.

(iii)    Ties  which  will  not  be  removed  during  the  use  of  a  scaffold should  be  inserted  and  maintained  at  a  frequency  of  one  for every 40m2 of the scaffold surface and should be reasonably evenly distributed over the scaffold face area, both horizontally and vertically.

(iv)   The  spacing  of  lines  of  ties  should  not  exceed  8.5m,  either horizontally or vertically, but at the same time individual ties should still be within the area rule above. Where the building/structure surface permits a staggered arrangement of ties, this should be adopted in preference to a rectangular pattern.

(v)    The tie tube should be horizontal or sloping downwards away from

the building.

(vi)    At the point where the attachment of the tie tube to the building/ structure is made, the building/structure should be strong enough to resist the forces applied to it.

(vii)  Ties should preferably be attached to both the inside and outside ledgers or standards and, if possible, at a point not more than 300mm from a braced standard.

(viii)  The attachment of the tie tube to the scaffold should preferably be next to pairs of standards which are ledger braced, as near to a node point as possible.

(ix)    The  couplers  for  ties  set  at  an  angle  to  the  building/structure should be swivels. The couplers for ties set at right angles to the building/structure and horizontally should be right angle couplers or another such arrangement of couplers which gives similar or adequate strength.

(x)     Where wire or banding ties are used, they should be turned round a node point of the scaffold or otherwise prevented from slipping along the ledger or standard by fixing safety couplers beside the point of attachment.

(xi)    Each tie should comprise an anchorage to the structure served and tying member connecting this anchorage to the scaffold. If a single anchorage is not strong enough to provide a safe working capacity of

6.25kN, two or more should be used or the design reconsidered.

(g)      Bracings

Bracings should be provided to stiffen the scaffold. The plane to be braced should, wherever practicable, be divided into a complete series of triangles by braces. These should be fixed as close as possible to intersections. A check should be made on the reduction in strength of the scaffold where a brace has to be omitted or where it cannot be fixed within 300mm of an intersection.

Ledger bracing:

(i)      Ledger bracing should be on alternate pairs of standards. Any pair of standards, which are ledger braced, should be made into a complete series of triangles.

(ii)    When the bay length is 1.5m or less, the ledger bracing may be fixed

to every third pair of standards.

(iii)    The ledger bracing should be fixed from ledger to ledger with right angle couplers when the lift is not to be boarded but may be fixed to the standards using swivel couplers.

(iv)    The ledger bracing on boarded lifts should be from under the outside ledger of a boarded lift down to the inside ledger of the lift below so as to avoid the toe-board.

(v)     The ledger bracing from the inside ledger to the guard-rail level of the lift below may be used provided that every pair of standards is so braced instead of every alternate pair.

(vi)    In scaffolding over footpaths, the ledger bracing may be omitted from the lowest lift provided the lengths of the standards in the lift are not in excess of 2.7m. When the height of the lowest lift is in excess of 2.7m, a knee brace should be inserted across the top corner of the lowest lift, commencing at approximately 1.8m from the ground. One such knee brace should occur on every pair of standards and be fixed with alternate slopes. On large scaffolds it is sometimes desirable to insert cross knee braces on every pair of standards, and a ledger should be fixed adjacent to where the knee brace meets the standard.

Facade bracing:

(i)      Longitudinal bracing should be provided to all scaffolds in which the movement along the facade of the building/structure is not prevented by other means.

(ii)     The  longitudinal  bracing  should  be  achieved  by  tubes  set  at between 35o and 55o to the horizontal, reaching from bottom to top of the scaffold. There are three principal forms:

–        individual tubes set in zig zag pattern, the top of a tube and the bottom of the next preferably being attached to the same transom;

–        a continuous tube, extended as necessary to cover the whole scaffold, only possible for wider scaffolds;

–        individual tubes as described in the first form above but all sloping the same way; the top of one is connected at a ledger/ standard intersection, and the bottom of the next is attached to the same pairs of standards.

In most situations, a combination of these should be appropriate. The

bracing tubes should be connected either in the following two ways:

–        to  every  lift  of  the  extended  transoms  with  right  angle couplers; or

–       to every standard with swivel couplers.

The first way above is to be preferred.

(iii)    The  brace  assembly  should  be  provided  at  intervals  along  the scaffold not exceeding 30m.

(iv)   The longitudinal bracing should be fixed as near to the standards as

possible.

(v)     The   longitudinal   bracing   should   include   the   lower   lift   being started  from  the  base  of  one  of  the  outside  standards.  In  the lower lift, when the bracing is started, a guard-rail should be placed through the braced bay to prevent people passing.

(vi)    The  joints  in  continuous  diagonal  bracing  should  be  made  by overlapping the two lengths of the tube by a distance of at least

300mm and joining them together with two parallel couplers. Or, the two tubes may be joined by a sleeve coupler or other coupler capable of sustaining the applied load.

Plan bracing:

(i)     Plan bracing should be provided to all portions of a scaffold which are

not otherwise stabilized against lateral distortion.

(ii)     It   may   be   joined   by   the   same   type   of   couplers   used   for longitudinal bracing and the same rules with regard to strength apply.

Couplers for fixing braces:

Right  angle  couplers  should  be  used  to  fix  braces  to  ledgers  or transoms and swivel couplers should be used for the attachment to standards. Other couplers may be used provided that they are capable of sustaining a safe working load of 5kN.

(h)      Erection tolerances

(i)      Standards should be vertical to within ±20mm in 2m (subject to a max. total deviation of 50mm).

(ii)    Bay length and width should be ±200mm on designated lengths,

and level to within ±20mm in 2m (subject to a max. total deviation of

50mm).

(iii)   Lift height should be ±150mm on the designated height.

(iv)    Nodes should be equal to or less than 150mm between coupler centres.

5.2.2  Metal putlog scaffold

All the requirements are the same as described in Section 5.2.1 above with the following additional points to be observed:

(a)     It should consist of a single row of standards parallel to the face of the building/structure and set as far away from it as is necessary to accommodate a working platform same as that required for a double-row metal scaffold, with the inner edge of the platform as close to the facade of the building/structure as is practicable. (See Figure 2 for details)

(b)     All the standards should be connected with a ledger fixed with right angle couplers and the putlogs are fixed to the ledgers with right angle or putlog couplers.

(c)    The  blade  end  of  the  putlog  tube  should  be  placed  horizontally on the brickwork/structure, etc. being built. But for the case of existing  building/structure,  the  old  putlog  holes  (if  any)  may be reused or others raked out, and the putlog blades may be inserted vertically.

(d)    Sole plates and base plates should be used under each standard and their requirements are the same as described in Section 5.1.2 above.

(e)     The  scaffold  should  be  tied  into  the  building/structure  at  the manner as described in Section 5.2.1(f) above.

(f)      Where  a  putlog  is  required  for  a  board  support  to  form  a working platform and it is opposite to an opening in the building/ structure such as a window or doorway, etc., the inside end of the putlog should be supported on an underslung bridle tube spacing between adjacent putlogs.

(g)    Longitudinal  bracing  should  be  required  at  intervals  not exceeding 30m but ledger bracing is not required in the finished scaffold.

(h)    The lift height should be no more than 1.35m.

(i)     Tie tubes should be attached by right angle couplers to the ledgers or standards.

5.2.3  General free-standing metal towers

(a)     These   metal   towers   are   free-standing   structures   which   are self-supporting  and  do  not  depend  totally  on  other  structures for their rigidity or stability. There are mainly three types of such towers:

(i)     Light duty access towers, stationary and mobile for use inside

buildings (imposed load not greater than 1.5kN/m2).

(ii)    Light duty access towers, stationary and mobile for use in the

open area (imposed load not greater than 1.5kN/m2).

(iii)   Heavy  duty  towers,  such  as  camera  towers  and  welding

platforms (imposed load in excess of 1.5kN/m2).

(b)     Free-standing towers situated externally and likely to be subject to wind forces should be the subject of calculations for wind forces and overturning.

(c)     All  free-standing  towers  should  be  vertical  and  built  on  firm foundations. If on sloping ground, they should be prevented from slipping. Towers inside buildings should be on level floors or adequately compacted sub-bases.

(d)    The towers should be adequately stiffened on all sides and in plan at

every alternate lift, starting at the base lift of mobile towers.

(e)    Access to and egress from the top of towers should be by stair/

ladder.

(f)      The working deck should be of adequate thickness. If boarded with scaffold boards, the supports of the boards should comply with the recommendations  of  the  table  in  Section  5.2.1  (c)(iv)  and  the boards, if short, should be prevented from sliding by battens nailed beneath the deck. The deck should be provided with toe-boards and guard-rails complying with the recommendations of Section 5.1.4. Generally, the deck should have at least one edge in the same vertical plane as one side of the tower base so that this edge can be placed up against the work to be done. The worker is thus not required to lean out over the guard-rail.

(g)     All  types  of  free-standing  structures  depend  for  their  stability either on their self-weight or on additional guys, anchors, outriggers or kentledge. The factor of safety for scaffold structures, i.e. the ratio of the overturning moment to the stabilizing moment, should be not less than 1.5. The overturning moment is due to eccentric weight, imposed loads and environmental loads. The stabilizing moment is due to the self-weight, if suitably centered, added kentledge and the anchor, gut or strut forces, if any.

(i)      Where kentledge is used, it should be fixed round the perimeter of the foot lift and a tube and fittings grid should be installed to receive and locate it. If castors are used, their capacity to take the extra load should be checked.

(ii)     Where anchor is used, anchor capacities are dependent on ground conditions and reference should be made to the manufacturer for the type, number and location of anchors. There are four types of anchorage commonly used :

Cross tubes attached to the foot lift :

Temporary stability can be achieved by using cross tube anchors attached directly to the bottom of the structure. The forces involved should be calculated and the necessary number of anchors inserted. The necessary number of safety couplers should be added to the base frame of the structure and the tensions in the standards catered for by sleeve couplers and lapping where necessary. (See Figure 3a for details)

Driven tube anchors attached to guys :

Driven tube anchors should not be used on a down slope towards the structure. They can be used in clay, sandy or gravelly ground. Tubes should be 1.75m long and penetrate

1.25m into the ground. They should be fixed together with tubes and fittings connected with right angle fittings in preference to lashings. The tubes should be set at right angles to the guy. The guy should be attached at the bottom of the front tube and prevented from slipping up by a scaffold fitting. (See Figure 3b for details)

Screwed in flight anchors :

They should be set in line with the guy and should be screwed in using a short length of scaffold tube through the ring. They will not penetrate so deeply on an uphill slope towards the guy and allowance for this should be made. (See Figure 3c for details)

Plate and pin anchors :

Plate and pin anchors should be used where the ground is too stoney or has shattered rock, limestone or chalk near the surface. The pins should be driven in at right angles to the guy and the anchors should be set so that the guys are flatter than

40o   to the horizontal. For square towers, a separate anchor

should be provided for each corner. (See Figure 3d for details)

(iii)   Guys for the metal towers should be of 10mm or 12mm diameter wire rope which should be attached to the scaffolding structure and to the ground tube or anchor by a single round turn and three bulldog grips. The recommended safety factor for guy ropes is 3:1. No tensioning device should be pulled up too tightly since the force required to pull a wire guy tight results in very considerable tension being placed on the ground anchorage and the structure before it has been loaded with the wind forces. All the guys should be attached to node points of the scaffold structure.

(h)     When  metal  towers  are  required  to  be  a  height  exceeding  the height to the least base dimension ratio recommended in Section

5.2.4 (a) to 5.2.4 (b) and Section 5.2.5 (a) to 5.2.5 (b) and a larger base cannot be built or extension buttresses cannot be fixed at the base, the tower should be constructed up to the maximum height allowed by the height to the least base dimension ratio and then tied, roped or guyed in four directions to the main structure which is being serviced. The tower may then be increased in height and should be additionally tied at levels of approximately every 6m.

(i)     Operation of free-standing metal towers :

(i)      The  user  should  apply  no  horizontal  force  at  any  working deck, e.g. by hauling heavy ropes or cables, and should not lift significant loads up the outside of the tower or attach a gin wheel on a cantilever tube unless the tower is specifically designed for this purpose.

(ii)     If large weights are to be hoisted to the top deck by block and tackle, adequate davits or brackets should be provided and the stability of the tower calculated for the suspension reaction at the top block which might be twice the lifted weight. If the towers are rectangular, the lifting tackle and ladders should be on the shorter side.

(iii)    Mobile towers should only be used on even ground, never on a slope which is sufficient to allow them to run away. Castors should normally be kept locked except when the tower is being relocated. When used on surfaces which have a cross fall and/ or a longitudinal fall, the user should be particularly careful to see that the brakes are on at all times other than whilst moving the tower. If there is any doubt as to the adequacy of the brakes, the wheels should be chocked.

(iv)   No worker or heavy material should be permitted on any mobile scaffold during its movements. The force to achieve resiting should be applied at the base.

5.2.4  Stationary metal towers

This is one of the commonly used free-standing metal towers in Hong Kong. There are different requirements when being used within and outside buildings:

(a)    Within buildings:

The height limit of these towers is achieved by restricting the ratio of the height to the least base dimension. Within buildings there are no environmental loads, but nevertheless some tendency to overturn a tower may occur from raising weights outside its base area, wrongful application of force at the top and normal operations on the top deck. To cater for this overturning moment, the height to least base dimension ratio should not be greater than 4. The height is measured from the floor to the level of the working deck or top lift whereas the least base width is the dimension, centre to centre, of the shortest side of the tower if it is rectangular.

(b)    Outside buildings:

(i)      The    height    to    the    least    base    dimension    ratio    for stationary  towers  outside  buildings  without  special  means of anchoring should not be greater than 3.5.

(ii)     Stationary  towers  outside  are  usually  exposed  and  are therefore subject to wind forces. Towers, even with a height to the least base dimension ratio less than 3.5, are unstable in locations exposed to high winds. For these circumstances, the wind forces should be calculated and the tower restrained by kentledge or guys to give a factor of safety against overturning of 1.5 in any direction.

(iii)    Besides, when the ground is soft, sole plates should be used and the tower should be maintained in the centre of the sole plate by the use of substantial nails or other means. When the ground is sloping, the sole plates should be dug in flat.

5.2.5  Mobile metal towers

This is also one of the commonly used types of free-standing metal towers in Hong Kong. They are fitted with castors at the bottom of the standards. The castors should be of the swivel type and fixed to the standards of the scaffold so that they cannot fall off if the leg is out of contact with the ground (See Figure 4 for details). There are different requirements when being used within and outside buildings:

(a)    Within buildings:

The height to the least base dimension ratio should be limited to 3.5. (b)    Outside buildings:

(i)      The height to the least base dimension ratio should not be greater than 3. When in use in exposed situations, the scaffold should be tied to the building it is serving.

(ii)     When a scaffold is used in location exposed to high winds, the wind forces should be calculated and the scaffold restrained by kentledge or guys etc., to give a factor of safety of not less than 1.5. Also the capacity of the castors to take the extra load should be checked.

No more than one working platform should be permitted on all mobile metal scaffold at any one time.

Technical requirements for safety in metal scaffolding – Erection/addition/alteration of metal scaffold

Leave a reply

Technical requirements for safety in metal scaffolding – Erection/addition/alteration of metal scaffold

5.1.4  Erection/addition/alteration of metal scaffold

(a)     Metal scaffolds shall be erected, added to, or altered by trained workmen  under  the  immediate  supervision  of  a  competent person. (Regulation 38E of the CSSR)

(b)     Work should be started from the bottom level to the top level and from the interior part to the exterior part.

(c)    The standards of the scaffolds should be plumbed.

(d)     The width of any working platform of the scaffold shall be not less than 400mm. (Third Schedule to the CSSR)

(e)     Every working platform shall be closely planked, boarded or plated, or of open metal work without any interstice exceeding 4 000mm2. (Third Schedule to the CSSR)

(f)      Every board or plank forming part of a working platform shall be of sound construction, adequate strength and free from patent defects  (Third  Schedule  to  the  CSSR).  The  plank  should  be straight-grained, sound and free from irregular knots, dry rot, worm holes, cracks and other defects affecting its strength. Also, the board should be sound and free from cracks and other defects affecting its strength.

(g)     Every board or plank forming part of a working platform shall be not less than 200mm in width and not less than 25mm in thickness or not less than 150mm in width when the board or plank exceeds

50mm in thickness. (Third Schedule to the CSSR)

(h)     Every board or plank forming part of a working platform shall not protrude beyond its end support to more than 150mm unless it is sufficiently secured to prevent tipping. It shall rest on at least 3 supports unless, taking into account the distance between the supports and the thickness of the board or plank, the conditions are such as to prevent undue or unequal sagging. (Third Schedule to the CSSR)

(i)     Every side  of a working platform  shall  be  provided with  suitable guard-rails. The height of a top guard-rail shall be between 900mm and 1 150mm above the platform. The height of an intermediate guard-rail shall be between 450mm and 600mm above the platform (Third Schedule to the CSSR). (See Figures 1 and 2 for details)

(j)      Toe-boards  and  end  toe-boards  shall  be  suitably  fixed  to  all working platforms and shall have a minimum height of 200mm (Third Schedule to the CSSR). They should be placed inside the standards. (See Figures 1 and 2 for details)

(k)     Space between platform and wall of a building or structure should be as small as practicable. Guard-rails should be provided if there is a risk of falling from height.

(l)     Working platforms should be cleared of debris like concrete waste. (m)   Working platforms should not be overloaded and the load should be

evenly distributed.

(n)    No shock loading on the platforms should be allowed.

(o)     The scaffold should be effectively braced to ensure stability of the whole structure.

(p)     The  bracings  should  extend  from  the  base  to  the  top  of  the scaffold.

(q)     If  electrical  equipment  such  as  power  hand  tools  or  electric installation including lighting is to be used on the scaffold, they should be of proper design and installation to prevent electrical hazard.

(r)      Where  a  scaffold  is  erected  adjacent  to  a  road  or  pathway, overlay or screen nets must be erected to envelop the scaffold for the protection of person or vehicular traffic against falling objects.

(s)     Safe  access  to  and  egress  from  place  of  work  should  be provided  for  the  scaffolders  and  the  users  of  the  scaffold.  One way of providing a safe access to and egress from a scaffold is to provide a safe gangway between the existing building/structure and the scaffold. Access and egress provided should be used and no climbing along the standards/ledgers of the scaffold should be allowed.

(t)      When a scaffolder or workman has to work in a place where it is  impracticable  to  erect  a  safe  working  platform  or  to  provide safe access and egress, the use of safety nets and safety belt attached                   to   a   secure   anchorage   point   or   an   independent lifeline  throughout  the  work  is  required.  Scaffolding  members should  not  be  used  for  anchorage  purpose.  Further  reference should be made to the Guidance Notes on Classification and Use of Safety Belts and their Anchorage Systems prepared by the Labour Department.

(u)     Particular attention should be drawn in the manual handling of heavy metal scaffolding components.

(v)     Scaffolding   members   should   not   be   used   as   supports   for lifting appliances unless the scaffold has been designed for such purpose.

Technical requirements for safety in metal scaffolding – Cast-in and drilled-in anchorages used as ties

Leave a reply

Technical requirements for safety in metal scaffolding – Cast-in and drilled-in anchorages used as ties

5.1.3  Cast-in and drilled-in anchorages used as ties

(a)    Cast-in anchorage

In some cases, it is possible to ‘build in’ scaffold ties into the fabric of the building during construction. A variety of screwed plates, sockets and nuts are available for setting into concrete during pouring, in a similar manner to formwork anchors, for subsequent use as scaffolding  ties. The  appropriate  bolts  should  be  welded  to scaffolding tubes or scaffolding fittings for use as tie attachments. Alternatively, the bolts may be used directly to attach this type of fitting. Ring bolts may also be used.

(b)    Drilled-in anchorage

A   variety   of   expanding   anchor   sockets   are   available   for fixing into holes drilled into hardened concrete. The attachments are similar to cast-in anchors. Care should be taken that the facade  material  is  a  structural  material  and  not  a  surface cladding with little or no strength. Anchor sockets and ring bolts rely  on  an  expanding  wedge  to  secure  the  anchor  into  the pre-drilled  hole. As  such,  overtightening  should  be  avoided  to prevent damage of the base material of the pre-drilled hole. Torque wrenches or other special tools supplied by the manufacturers should be used to fix the anchors, the ring bolts or other devices inserted and tightened by hand. Drilled-in anchorages should be tested before use.

(c)    Anchorages should be tested to ensure that they are of sufficient strength. They should be tested in accordance with BS 5080 or other equivalent national/international standards or provisions.

Technical requirements for safety in metal scaffolding – Support for metal scaffold

Leave a reply

Technical requirements for safety in metal scaffolding – Support for metal scaffold

5.1.2  Support for metal scaffold

(a)    The  stability  of  the  ground  or  supporting  structure  should  be

justified by recognized engineering principles.

(b)  The ground or supporting structure for a scaffold should be adequate to carry and dispose the load imposed both locally at each standard and, in general, to carry the design loads of the scaffold without undue settlement.

(c)     The ground on which a scaffold is constructed should be solid, levelled and rammed to give a hard surface, and should be strong enough to keep the scaffold upright. Soil should be compacted or consolidated and as far as practicable, water be drained off.

(d)    Hard surface: on surfaces such as steel and concrete where there is adequate hardness and thickness to prevent the scaffolding tubes from penetrating into the surface, the standards can be placed directly on the surface but preferably to be placed on a base plate.

(e)  Pavements and other surfaces of intermediate hardness: on surfaces such as hard asphalt, timber and flooring, where there is a possibility of the standards deforming the surface, base plates or metal packing plates should be used at the bottom of the standards.

(f)      Other surfaces: on soil, ash, hoggin, gravel, soft asphalt and any type of flooring or paving which would be penetrated by a standard with a base plate beneath it or if there is doubt about the surface, there should be a further spreading of the load by a sole plate of timber or other suitable material.

(g)     The sole plate area beneath one standard should be at least 0.1m2 with the least dimension of 219mm, and if the sole plate is of timber, it should be not less than 35mm thick. Where the ground is soft or has been disturbed, the sole plate area should be not less than 0.17m2 when individual sole plates are used.

(h)     The  ground  or  soil  beneath  the  sole  plate  should  be  well compacted and free from irregularities, which would make the sole plate unstable or poorly bedded.

(i)     On sloping supports, the base of the scaffold should be effectively prevented from sliding. An appropriately shaped wedge should be inserted to the void between each standard’s base plate and the sloping support to ensure tightness and verticality. To resist lateral loads, the base of the scaffold should further be adequately anchored to the sloping support.

(j)      The supports for a scaffold should be maintained in an adequate condition  as  described  in  this  section  during  the  life  of  the scaffold.

 

Technical requirements for safety in metal scaffolding

Leave a reply

Technical requirements for safety in metal scaffolding

5.1  General requirements

5.1.1  Materials

(a)  Sufficient material should be provided for and used in the construction of scaffolds.

(b)     Scaffolding  components  should  be  of  sound  material,  good construction, adequate strength and free from patent defects and should be properly maintained.

(c)     Boards and planks used in the construction of working platform should be straight-grained and free from large knots, dry rot, wormholes and other dangerous defects. Where necessary, they should be protected against splitting.

(d)    These  boards  and  planks  should  be  unpainted  so  that  any defects are readily visible.

(e)     Timber scaffold boards and their permitted tolerances should comply with BS 2482 or other equivalent national/international standards or provisions.

(f)      All   scaffolding   components   should   comply   with   BS   1139, BS EN 39, BS EN 74, BS EN 1004 and BS EN 12810 or other equivalent national/international standards or provisions. Hot dipped galvanized, painted or unprotected tube may be used in scaffolding structures. Unprotected tube should generally not be used in water and particularly not in marine structures. If used in such conditions, tubes should be thoroughly cleaned afterwards, carefully inspected, e.g. for signs of excessive corrosion and only returned to stock if suitable.

(g)  Tube ends should be free from distortion, corrosion, splits, laminations, surface flaws and undue rust. Used tubes should be free from cracks, splits and excessive corrosion (for example, corroded steel tube should be wire brushed for checking) and be straight to the eye. The ends of load-bearing tubes should be cut cleanly and squarely with the axis of  the tube and should not show excessive

wear. Sections of tube, which have been deformed or creased by abuse, should be cut out and discarded. Where tubes have become thin or split at the ends, these should be cut off and the cuts should be at right angles to the axis to the tube.

(h)     The   safe   working   loads   for   individual   couplers   and   fittings should comply with BS EN 12811 or other equivalent national/ international  standards  or  provisions.  Special  attention  should be paid to the use of joint pins because they cannot bear any tension. All couplers and fittings should be free from rust and distortion, worn threads and damaged bolts and should be maintained  in  lubricated  condition.  The  nuts  should  be  run  on their bolts to ascertain that they have a free-running fit. Spanners and  podgers  should  have  lengths  as  recommended  by  the coupler manufacturer.

(i)      Regarding  the  loads  on  working  platforms,  all  decking  units  of working platforms should have adequate strength to meet the recommendations for the appropriate duty of that specified in the following table:

 

Minimum Imposed Loads
Duty Use of platform Distributed load on platform Concentrated load to be applied on plan

over any square with a

300mm side and at the end portion of a cantilever
 

Inspection and very light duty

  

Inspection, painting, stone cleaning, light cleaning and access

  

0.75 kN/m2

  

2 kN
Light duty Plastering, painting, stone cleaning, glazing and pointing 1.5 kN/m2 2 kN
General

purpose

 General building work including brickwork, window and mullion fixing, rendering, plastering 2 kN/m2 2 kN
Heavy duty Blockwork, brickwork,

heavy cladding

 2.5 kN/m2 2 kN
Masonry or

special duty

 Masonry work, concrete blockwork and very heavy cladding 3 kN/m2 2 kN

Scaffold  boards  of  working  platforms  should  be  cleaned  on return from a construction site prior to stacking. They should be stacked flat and raised from the ground by cross battens. The end hoops or other means of end protection should be replaced or refixed as necessary. Boards with split ends should be cut down to  form  boards  of  reduced  length.  Boards  should  be  inspected after each job. Any boards showing signs of ill-treatment, abuse, decay or excessive warp should be discarded. Damaged or suspect sections should be cut off and destroyed. Care should be taken in the use of boards. Any over stressing (for example, that caused by impact loading) likely to cause unseen damage should be avoided. They should not be used as ramps or platforms over long spans, nor should they be put on the ground where vehicles or other loads can be put on them. Boards, which show evidence of vehicle tyre marks, should be destroyed. Where boards are treated for fire retardant purposes, care should be taken to select a process, which would minimize the loss of board strength.

Managing safety and health at metal scaffolding work

Leave a reply

Managing safety and health at metal scaffolding work

A safety management system and a safe system of work should be developed, implemented and maintained for the safety and health at work of workers. Further reference should be made to the Factories and Industrial Undertakings (Safety Management) Regulation. Among other things, the following actions should also be taken into account:

4.1  Design and initial planning

A  construction   project   should   be   designed   with   safety   in   mind.   This approach makes it possible to eliminate or minimize the work hazards by proper planning and design of the methods of construction, sequences of activities, coordination, etc.

4.1.1  During the design of a metal scaffold, attention should be paid in the following areas:

(a)   The safe scaffold and its erection/alteration/dismantling for all different stages of construction should be designed and planned well beforehand.

(b)     The  safe  method  of  scaffolding  devised  should  be  kept  under continual review.

(c)     The strength and stability of the scaffold throughout all stages of scaffolding should be ensured.

(d)     The strength of scaffolding members such as tubes and couplers should be ensured. Reference should be made to the procedures laid down in relevant standards of the International Organization for Standardization or equivalent procedures for their sampling and mechanical testing.

(e)    Realistic  assessment  of  loadings  on  the  scaffold  at  all  work stages should be made. In considering the wind load on the scaffold, reference should be made to the Code of Practice on Wind Effects in Hong Kong, 2004 (Buildings Department).

(f)      Safe  access  to  and  egress  from  the  working  places  should  be provided.

(g)    Effective  bonding  system  to  earth  should  be  provided  to  the scaffold.

(h)    Additional  features  such  as  attachment  points  for  ladders, working platforms, guard-rails and toe-boards should be provided for the protection of workers using the scaffold. Safety nets and safety belts should also be provided for the protection of scaffolders.

(i)      Scaffolding  components/materials/equipment  should  be  handled, lifted, stored, stacked and transported safely.

(j)      The time when the scaffold would be erected and dismantled should be decided in the design and planning stage. The scaffold should be dismantled as soon as it is no longer required to be used.

4.1.2  Specification for scaffolding contract document:

(a)     Specification     for     scaffolding     contract     document     should incorporate    particular   requirements   and   essential   information for the scaffolding work to be planned and implemented safely. (For example,  the  provision  of  design  drawings  and  method statement; phasing of work – particularly with other contractors; periodic maintenance and repair of scaffold.)

(b)    Special   requirements   relating   to   compliance   with   safety legislation should be highlighted and, where appropriate, these items should be included in the Bills of Quantities.

(c)     Depending on the size of the project and/or the complexity of the work involved, tenderers for the scaffolding work should be required to submit an outline scaffolding plan at tendering stage, giving sufficient information to demonstrate their intended safe system of work.

4.1.3  Coordination and communications:

(a)     There should be close liaison between all relevant parties even at the design and planning stage.

(b)     Effective lines and systems of communication should be devised for each stage of the scaffolding work and a person should be assigned to maintain effective communication.

4.1.4  Initial planning:

(a)    Site considerations and risk assessment

Potentially  hazardous  site  features  and  other  aspects  likely  to impair safe scaffolding should be identified. The risk arising from each individual hazardous event should be evaluated according  to its probability and consequence. The following special conditions of the site should be taken into account:

(i)     The existence of overhead electric power lines.

(ii)    The   existence   of   overhead   signboards   or   projections,

particularly those in the urban areas.

(iii)    The  existence  of  buried  services,  including  underground electric cables, gas or other fuel pipelines.

(iv)   The existence of storage tanks.

(v)    Restricted access to, and onto the site.

(vi)    Restricted space for erection, manoeuvring, storage and, if required, for on-site pre-assembly or fabrication.

(vii) Low ground bearing pressures that may be due to, for example, made ground or existing underground services or structures.

(viii) The proximity and condition of other buildings and premises that may by itself or so-induced special wind effect (for example, funnelling effect) affect the planned method of scaffolding.

(ix)   The shape and the structure of the building. (x)    The juxtaposition of the public and the site. (xi)   The activities of other contractors.

(xii)  The  existence  of  noxious  gases,  chemicals,  fluids  or  dust

emitted from processes on or around the site.

(xiii) The proximity of the site to seashore where the strength of the scaffolding may be affected by seawater.

(b)    Preliminary method statement

The preparation of a preliminary method statement is an important part of planning for a safe system of work in scaffolding. Where appropriate, a preliminary method statement should include:

(i)      the arrangements for coordination and the responsibilities and authority of supervisory personnel during scaffolding work;

(ii) the scaffolding sequences including erection and dismantling;

(iii)    the  methods  of  ensuring  stability  with  due  consideration of future construction activities (for example, trench work, external building services /facilities installation);

(iv)    the detailed scaffolding work method which should ensure that the work could be carried out safely;

(v)    the construction tolerance;

(vi)    the assessed maximum allowable loading (includes vertical and lateral loads) on the scaffold/working platform;

(vii)  the provisions to prevent falls from height, including safe means

of access and egress and safe places of work;

(viii) the protection from falls of materials, tools and debris, and the

provision of catch-fans and protective screens at the scaffold;

(ix)   the provision of suitable plant, tools and equipment;

(x)    the   arrangements   for   delivery,   stacking,   storing   and movement on site for scaffolding components, materials and equipment;

(xi)   the details of site features, layout and access; and

(xii)  the contingency arrangements.

4.2  Selection of subcontractor for metal scaffolding work

4.2.1  If   a   subcontractor   is   to   be   engaged   in   metal   scaffolding   work, whether he would make adequate provisions for safety and health should be an important selection consideration. Selection criteria should also include the ability of the subcontractor in providing a good scaffolding plan.

4.2.2  During the process of selection, the subcontractor should be required to submit an outline scaffolding plan, giving preliminary information to demonstrate the intended safe system of work. Depending on the complexity of the project, the outline scaffolding plan should briefly describe items such as safety organization, communication, monitoring, equipment, facilities, emergency procedures, accident reporting, and accident investigation procedures.

4.2.3  After the subcontractor has been appointed, he is required to finalize a detailed scaffolding plan on the basis of the outline scaffolding plan if any, for agreement in writing. The detailed scaffolding plan should spell out the ways and means to carry out work safely and effectively in order to fulfil the objective of protecting workmen at work. The detailed scaffolding plan should also be incorporated into the safety plan of the main project.

4.3  Site management and procedures

4.3.1  Managing for safe erection/alteration/dismantling

Safe  working  methods  and  practices  on  site  should  be  ensured  as follows:

(a)    Preparation and use of a detailed method statement

The extent of detail in a detailed method statement will depend upon the size and/or complexity of the work, with a simple job requiring a simple method statement and repetitive tasks being covered by standard sheets. Preliminary method statement produced at the planning stage should be developed into a detailed method statement that should be incorporated into the detailed scaffolding plan. The whole method statement should be reviewed and updated as necessary so that it remains current. It should be distributed to all those concerned with the supervision of scaffolding work.

(b)    Thorough and active contract coordination both on and off site

Coordination and liaison between parties should be maintained throughout the job. Any changes in previously agreed procedures must  be  verified  by  the  person  responsible  for  coordination  as being safe before they are implemented. Matters that will contribute to safe scaffolding work on site, including the availability of information, plant and manpower, and the quality and supply of materials should also be coordinated.

(c)    Implementation and maintenance of effective communications

To  ensure  that  precautions  for  safe  scaffolding  outlined  in  the method  statement  are  followed,  lines  of  communication  should be clearly designated, with the responsibility for implementing the method statement well defined.

(d)    Contingency plan for adverse weather conditions

Weather conditions that could have an adverse effect on the scaffolding work such as rain, high wind, lightning or typhoon, and those causing poor visibility, such as fog, mist or glare should be constantly monitored.

If  a  decision  is  made  to  stop  work,  then  measures  should  be taken to maintain the stability of the scaffold and the plant, equipment and works erected on the scaffold.Also, all personnel should be safely and efficiently evacuated from the scaffold. After the adverse weather, the scaffold should be inspected and certified in safe working order by a competent person and all the plant, equipment and works erected on the scaffold should be checked and confirmed to be in order before work is to be restarted.

(e)    Provision of suitable staff

No scaffold shall be erected on the site or substantially added to, altered  or  dismantled  except  under  the  immediate  supervision of a competent person and by trained workmen possessing adequate experience of such work (Regulation 38E of the CSSR). Training should be a continuing process with on-the-job instruction and formal training sessions provided as appropriate (refer to Section 4.6).

(f)     Provision of protective equipment

Protective  equipment  that  is  necessary  and  appropriate  for  the work  should  be  provided.  Examples  of  protective  equipment are: safety helmets, safety nets and safety belts with suitable anchorage.

4.3.2  Preparing the site and the work

(a)     Plans  and  drawings  should  be  checked  for  matters  relating  to scaffolding safety before work is to be started.

(b)     The need to exclude other personnel from scaffolding areas when scaffolding work is in progress should be considered.

(c)    Site   inspection   should   be   conducted   to   check   the   physical

conditions, the hazards involved and other special features. (d)    The ground condition should be made firm, level and suitable.

(e)    The  maximum  safe  loading  (includes  vertical  and  lateral  loads)

imposed on the scaffold should be assessed, and strictly adhered to.

(f)      The scaffolding members should be checked for their fitness before despatching to the site. Defective materials should be prohibited to be used and should be removed from site as soon as possible. During their stay on site pending for removal, they should be properly labelled to show that they are defective and should not be used.

(g)    A suitable  place  should  be  provided  at  the  site  for  storage  of scaffolding members and the associated materials, tools or equipment. Also, they should be properly stacked and tied to prevent accidental displacement and collapse. The storage area should be clearly shown on the site plans.

(h)     Documents  such  as  scaffolding  plan,  method  statement,  design drawings and specifications of the scaffold, etc. should be made available to all parties concerned in good times.

4.4  Working places and access

4.4.1  Working platform of scaffold

(a)     A  method   statement   for   construction   of   a   working   platform should be devised. Please refer to Section 4.3.1 (a) on method statement.

(b)    Guard-rails  and  toe-boards  shall  be  installed  at  edges  where persons are liable to fall from height. The guard-rails shall have adequate  strength  and  be  securely  fixed.  The  height  of  a  top guard-rail  shall  be  between  900mm  and  1 150mm  above  the platform.  The  height  of  an  intermediate  guard-rail  shall  be between 450mm and 600mm above the platform. The height of a toe-board shall be not less than 200mm (Third Schedule to the CSSR).

4.4.2  Safety net

Provision of a workplace without risk of falling should always be the first consideration. However, if this is not practicable, safety nets and safety belts shall be used (Regulation 38H of the CSSR). Reference should be made to national/international standards or provisions for the standards of safety nets and safety belts.

4.4.3  Safety belt

In all the circumstances of the case, if it is impracticable to provide safety net, wearing of safety belt with effective anchorage system is required as the last resort for fall prevention (Regulation 38H of the CSSR). Further reference should be made to the Guidance Notes on Classification and Use of Safety Belts and their Anchorage Systems prepared by the Labour Department. It is strongly recommended that, when a choice of safety belt is possible, a safety harness incorporating buttock straps, as distinct from a general purpose safety belt, should be used.

4.4.4  Provision of catch-fan and protective screen

(a)    At  least  a  sloping  catch-fan  at  not  more  than  15m  vertical

intervals  to  give  a  minimum  horizontal  projection  coverage  of

1 500mm  should  be  provided.  The  sloping  catch-fan  should consist  of  timber  boarding  and  a  layer  of  galvanized  metal sheeting, both of adequate thickness to capture and retain falling objects.

(b)     A suitable receptacle should be provided within each catch-fan to trap falling objects. The weight of the receptacle should not affect the stability of the catch-fan.

(c)     The sloping catch-fan and receptacle should remain in place until all works are completed.

(d)     On  the  face  of  the  scaffold,  suitable  protective  screen  of  fire retardant  material  should  be  provided  to  confine  falling  objects. If tarpaulin is being used as protective screen, its fire retardant characteristic should meet the requirements of BS 5867-2:2008 (Type B performance requirements) or other equivalent national/ international standards or provisions.

4.5  Monitoring safety performance

4.5.1 Requirements on safety and health, particularly those relating to compliance with safety legislation, are advisable to be incorporated into the conditions of contract for engagement of subcontractor for metal scaffolding work or other subcontractors using the scaffold.

4.5.2  Regular records on the safety conditions of the scaffolding should be kept.

Such records should consist of detailed information on work hazards, precautions taken, accident analysis and recommendations. These records should be constantly reviewed for hazard identification and improvement.

4.5.3 Workmen’s feedback on the safety conditions of the site should be encouraged and as far as possible documented.

4.5.4 A monitoring system should be developed, implemented and maintained on site for checking the safety performance of the subcontractor for metal scaffolding work or other subcontractors using the scaffold against the requirements mentioned in Section 4.5.1.

4.6  Training of metal scaffolders

4.6.1  The objective of training is to increase the efficiency of workers and to improve safety performance in erecting, altering, maintaining and dismantling scaffolds. The importance of ensuring that workers who erect, alter, maintain and dismantle scaffolds are fully competent is obvious, but the degree of skills which are required differ according to the duty to be performed. There is a great span of proficiency and experience required. Properly controlled training is therefore vital for safety and it would eventually attract a better type of man to make a career in the industry. Before training of the scaffolders is to be considered, they should be physically fit for the scaffolding work first.

4.6.2  Training  of  scaffolders  needs  to  relate  to  basic  site  safety,  familiarity with everyday hazards and the requirements for a safe place of work. In general, training for scaffolders should start at ground level, where basic  skills  can  be  acquired,  and  when  scaffolders  are  proficient, using   those   skills   at   increasing   height   would   be   appropriate. Training should continue after basic skills have been acquired to ensure that scaffolders  are  familiar  with  improvements  in  techniques,  the  use of  newly  developed  equipment/materials,  and  to  ensure  that  safe methods of work continue to be used.

4.6.3  When   a   new   scaffolder   is   employed,   the   management   should ascertain the previous safety training of him, and should not assume that any scaffolder has a particular skill or training without seeing some proof or demonstration. Induction training will be needed to explain such matters as the company’s safety policy/organization, company safety rules, accident reporting requirements, etc. Besides, training/instruction would be necessary when the new scaffolder first starts on a project, to cover the particular requirements of the site such as emergency procedures, any special hazards and the safety aspects of the scaffold.

 

Issue of improvement notice and suspension notice under the Occupational Safety and Health Ordinance

Leave a reply

Issue of improvement notice and suspension notice under the Occupational Safety and Health Ordinance

3.3.1  Section 9

This section empowers the Commissioner to serve on an employer or an occupier of premises where a workplace is located an improvement notice requiring the rectification of contravention against safety legislation within a specified period.

3.3.2  Section 10

This  section  empowers  the  Commissioner  to  serve  on  an  employer who   is   responsible   for,   or   an   occupier   of,   premises   where   a workplace is located a suspension notice requiring suspension of an activity or use of premises or of any plant or substance where there is an imminent risk of death or serious bodily injury.

 

Principal safety and health legislation relating to safe metal scaffolding in Hong Kong

Leave a reply

Principal safety and health legislation relating to safe metal scaffolding in Hong Kong

The following is a summary of the statutory provisions in relation to safe metal scaffolding under the Factories and Industrial Undertakings Ordinance and its subsidiary legislation and the Occupational Safety and Health Ordinance. It is advisable to refer to the relevant Ordinances and regulations for full details of the statutory provisions summarized in this part or referred to in other parts of the Code.

3.1  General duties provisions under FIUO

Sections 6A and 6B of the Ordinance impose general duties on proprietors and persons employed with regard to the health and safety at work in industrial undertakings. In a construction site, these provisions do not only bind the principal contractor of the site. Subcontractors who are employers and who have management or control of construction activities within the site are also regarded as proprietors and are therefore bound by Section 6A. Besides, with regard to metal scaffolding works, workers using metal scaffolds and scaffolders, who are employed to work in the site are also bound by Section 6B.

3.1.1  Section 6A(1)

The   general   duties   imposed   on   the   proprietor   of   an   industrial undertaking  are  to  ensure,  so  far  as  is  reasonably  practicable,  the health  and  safety  at  work  of  all  persons  employed  by  him  at  the industrial undertaking.

3.1.2  Section 6A(2)

These general duties extend to include five specific areas:

(a)     The  proprietor  shall  provide  machinery,  equipment,  appliances and other plant that are, so far as is reasonably practicable, safe and without risks to health and must maintain them in that condition. He must also ensure that the systems of work are safe and without risks to health.

(b)     The proprietor shall make adequate arrangements for ensuring, so far as is reasonably practicable, safety and absence of risks to health in  connection  with  the  use,  handling,  storage  and transport of articles and substances.

(c)    The proprietor shall provide such information, instruction, training and supervision as is necessary to ensure, so far as is reasonably practicable, the health and safety at work of all persons employed by him. The information to be provided should include information about the hazards in the workplace and the necessary precautions to be adopted.

(d)    The proprietor shall ensure that, so far as is reasonably practicable, any place of work under his control is kept safe and without risks to health. This requirement covers not only buildings, but also includes,        for   example,   open   sites   and   temporary   structures such as scaffolds. The proprietor shall also ensure, so far as is reasonably practicable, the provision and maintenance of means of access to and egress from the workplace that are safe and without risks to health.

(e)     The   proprietor   shall   provide   and   maintain   for   all   persons employed by him a working environment that is, so far as is reasonably practicable, safe and without risks to health.

3.1.3  Section 6B(1)

The general duties imposed on every person employed at an industrial undertaking while at work are as follows:

(a)     The person employed shall take reasonable care for the safety and health of himself and of other persons who may be affected by his acts or omissions at work.

(b)     Also,    he    shall    co-operate    with    the    proprietor    or    other persons  so  far  as  is  necessary  to  enable  them  to  perform  or comply with the safety duties or requirements imposed on them by the Ordinance.

3.2  Construction Sites (Safety) Regulations

The CSSR are to protect workmen in the construction industry. These regulations  lay  down  legal  requirements  to  ensure  the  safety,  health  and welfare   of   workmen   on   construction   sites.   In   respect   of   scaffolding safety, the contractors/workmen are subject to the requirements of the following regulations:

3.2.1  Regulations 38A and 38AA

These regulations specify general provisions for ensuring safety of places of work, safe means of access to and egress from places of work and that no person gains access to any place on the site where any hazardous conditions are present.

3.2.2  Regulation 38B

This    regulation    requires    that    adequate    steps    such    as    the provision, use and maintenance of working platforms, etc. shall be taken to prevent any person from falling from a height of 2 metres or more.

3.2.3  Regulation 38C

This regulation requires the provision of safe scaffolds, ladders, etc. and ensures their use where work cannot be safely done on or from the ground or from part of a permanent structure.

3.2.4  Regulation 38D

This regulation requires that all the scaffolds, ladders, etc. shall be so designed, constructed, maintained and every part thereof so securely supported or suspended as to ensure that they are stable. Besides, all such scaffolds, ladders, etc. shall be made of suitable and sound materials of sufficient strength.

3.2.5  Regulation 38E

This regulation requires that only trained workmen with adequate experience and under the supervision of a competent person shall erect, alter or dismantle scaffolds.

3.2.6  Regulation 38F

This regulation requires that a scaffold shall not be used unless it has been inspected by a competent person:

(a)    before being taken into use for the first time;

(b)     at regular intervals not exceeding 14 days immediately preceding each use of the scaffold;

(c)     after   any   substantial   addition,   partial   dismantling   or   other alteration, exposure to weather conditions likely to have affected its strength or stability or to have displaced any part,

and a report has been made by the person carrying out the inspection on Form 5, which includes a statement to the effect that the scaffold is in safe working order.

3.2.7  Regulation 38H

This regulation requires the use of safety nets and safety belts when it is impracticable to provide safe scaffolds.

3.2.8  Regulation 38I

This regulation requires that any workman who has been provided with a safety belt shall wear the safety belt and keep it attached to a secure anchorage.

3.2.9  Regulation 48

This regulation requires that suitable safety helmets shall be provided for every workman; and all reasonable steps shall be taken to ensure that no workman remains on site unless he is wearing a suitable safety helmet.

3.2.10 Regulation 49

This  regulation  requires  that  scaffolding  materials  and  waste materials, tools and other objects, shall not be thrown, tipped or shot down from height. Where proper lowering by lifting appliances or gear is impracticable or demolition is being carried on, steps shall be taken to protect workmen from being hit by falling debris.

3.2.11 Regulation 52

This regulation requires that all platforms, gangways, etc. shall be kept

clear of any loose materials that are not required for immediate use.

3.2.12 Third Schedule to the CSSR

This schedule relates to the protection of any person from falling from a height of 2 metres or more. (See Appendix II for details)

 

Metal Scaffolding Safety – Interpretation

Leave a reply

Metal Scaffolding Safety – Interpretation

Unless otherwise defined in this Code of Practice, the terms used in this Code of Practice have the same meaning as those in the Factories and Industrial Undertakings Ordinance and the Construction Sites (Safety) Regulations, and

2.1  ‘FIUO’  is  the  abbreviation  for  the  Factories  and  Industrial  Undertakings

Ordinance, Chapter 59.

2.2  ‘CSSR’ is the abbreviation for the Construction Sites (Safety) Regulations,

subsidiary legislation of the Factories and Industrial Undertakings Ordinance.

2.3  ‘competent person’

2.3.1  A competent person, in relation to any duty to be performed by such a person under the CSSR, means a person who is:

(a)     appointed for that purpose by the contractor required by the CSSR to ensure that the duty is carried out by a competent person; and

(b)    by   reason   of   substantial   training   and   practical   experience,

competent to perform the duty.

2.3.2  As a general guidance:

(a)     ‘substantial training and practical experience’ of a competent person in respect of metal scaffolding refers to a person

(i)      who    has    satisfactorily    completed    a    full-time    formal training in metal scaffolding works organized by the Construction Industry              Council   Training   Academy   (CICTA)   or   other similar     metal    scaffolding    training    courses/programmes and possesses an experience of 4 years or more in metal scaffolding works (inclusive of experience under the formal training period); or

(ii)     who has at least possessed a higher certificate in civil/structural engineering or other similar disciplines and has satisfactorily completed a metal scaffolding training course/programme organized  by  the  CICTA or  other  similar  metal  scaffolding training courses/programmes and possesses an experience of 1 year or more in metal scaffolding works (inclusive of experience under the formal training period); or

(iii)    who   has   satisfactorily   passed   the   trade   test   on   metal scaffolding  of  the  CICTA and  possesses  an  experience  of

4  years  or  more  in  metal  scaffolding  works  (inclusive  of

experience under the formal training period),

and has the ability to read and understand the scaffolding plan, design drawings, specifications and method statement of the scaffolding  work  in  order  to  competently  supervise  the scaffolding   work   and   certify   that   the   scaffolding   is   in   safe working order. He should also be capable of identifying existing and predictable hazards in the surroundings or working conditions that are unsanitary or hazardous to employees.

(b)     A competent  person  should  be  appointed  in  writing  and  should have authorization to take prompt corrective measures to eliminate existing and predictable hazards mentioned above.

2.4  ‘trained workman’

A trained workman in respect of metal scaffolding refers to a scaffolder who is  responsible  for  on-site  erection,  addition,  alteration  and  dismantling  of metal scaffold under the immediate supervision of a competent person, and has satisfactorily completed a formal training in metal scaffolding works equivalent to any of those mentioned for a competent person or has satisfactorily passed the intermediate trade test for metal scaffolder of the CICTA and possesses at least

1 year of experience in metal scaffolding works (inclusive of experience under the formal training period). This Code of Practice also recognizes scaffolders who are registered skilled, semi-skilled, skilled (provisional) or semi-skilled (provisional) workers under the Construction Workers Registration Ordinance (Cap. 583) for the trade of metal scaffolder as trained workmen.

2.5  ‘Form 5’ is a form approved by the Commissioner for Labour for the purposes of

Regulation 38F(1) of the CSSR. A sample of the form is at Appendix I.

2.6  ‘ladder’ includes a folding step-ladder.

2.7  ‘place of  work’ means any place which is used by any person for the purposes of

(a)    construction work; or

(b)     any work activities arising from, or in connection with, construction work,

and includes any place to which such a person has access whilst at work.

2.8  A   ‘professional  engineer’  means  an  engineer  of  structural  or  civil discipline. He should be a corporate member under the constitution of the Hong Kong Institution of Engineers or equivalent and should have adequate training and experience, and be able to justify how and why the scaffold he designed can safely resist the imposed loads in accordance with recognized engineering principles.

2.9  ‘safety belt’ includes a safety harness.

2.10 ‘scaffold’  means  any  temporarily  provided  structure  on  or  from  which persons perform work in connection with operations or works to which the CSSR apply, and any temporarily provided structure which enables persons to obtain access to or which enables materials to be taken to any place at which such work is performed, and includes any working platform, gangway, run, ladder or step- ladder (other than an independent ladder or step-ladder which does not form part of such a structure) together with any guard-rail, toe-board or other safeguards and all fixings, but does not include a lifting appliance or a structure used merely to support such an appliance or to support other plant or equipment.

 

METAL SCAFFOLDING SAFETY – Introduction

Leave a reply

METAL SCAFFOLDING SAFETY – Introduction

1.1    This   Code   of   Practice   for   Metal   Scaffolding   Safety   is   issued   by   the Commissioner  for  Labour  under  Section  7A of  the  Factories  and  Industrial Undertakings Ordinance, Chapter 59. It provides practical guidance for the compliance with the requirements set out in Sections 6A & 6B of the Factories and  Industrial  Undertakings  Ordinance  and  the  requirements  of  the  Construction Sites (Safety) Regulations regarding the safety in metal scaffolding. In this Code, metal scaffolding refers to scaffolding with metal components as structural skeleton. The advice contained in this Code should not be regarded as exhausting those matters that need to be covered by the relevant safety legislation. Compliance with this Code of Practice does not confer immunity from relevant legal requirements.

1.2    This Code of Practice has a special legal status. Although failure to observe any provision of this Code is not itself an offence, that failure may be taken by a court in criminal proceedings as a relevant factor in determining whether or not a person has breached the relevant safety and health legislation under the Factories and Industrial Undertakings Ordinance.

1.3    Metal scaffolding can be used for different purposes in different construction activities. In Hong Kong, it is commonly used as the supporting scaffolding in a falsework system. Collapse of falsework due to reasons such as insufficient strength to carry the imposed loads or inadequacy in design and construction frequently occurs and has inflicted heavy casualties to workers working on it. In order to prevent collapse of falsework on construction sites, this Code of Practice also highlights good practices that have frequently been overlooked.

1.4    Section 5 of this Code of Practice has given technical guidance that should be followed in respect of metal scaffolding safety. If in any special situation where such requirements need to be modified, the stability and strength of the scaffolds should be justified by recognized engineering principles and national/ international standards or provisions so that equal or even higher safety standards can be achieved.

1.5   The statutory provisions summarized or referred to in this Code of Practice are

the provisions in force as at 1 January 2013.