COP v3.0:site-practice; safety

12.1 Safety 

The NZBC requires that people are safeguarded from injury during construction but this relates to injury as a result of structural failure rather than due to a mishap. 

Health and Safety at Work Act 2015 covers safety in workplaces generally.

Object of Act

The object of this Act is to promote the prevention of harm to all persons at work, and other persons in or in the vicinity of a place of work.

12.1.1 Responsibilities 

Compliance with the legal requirements of the HSE Act is not the only responsibility of anyone associated with working at height.
Employers have a duty of care to take all practicable steps to ensure the safety of employees, to provide and maintain a safe working environment, and to provide and maintain facilities for the safety and health of employees.
They must also ensure that equipment is safe, that working arrangements are not hazardous, and that procedures are in place to deal with any emergencies that may arise.

Taking all practicable steps means doing what is reasonable and possible to be done in the circumstances, taking into account:

  • the severity of any injury or harm to health that may occur;
  • the degree of risk or probability of that injury or harm occurring; and
  • the availability, effectiveness and cost of the possible safeguards.

Employers are also responsible for the health and safety of people who are not employees and must take all practical steps to ensure that employees do not harm any other person, including members of the public or visitors to the site.

The HSE Act requires employers to keep a register of work-related accidents including every accident that harmed or might have harmed someone. Employers are required to notify serious harm that occurs to employees to the nearest Worksafe office within seven days.

Employers are also required to investigate all these accidents to determine whether they were caused by a significant hazard.

If a person suffers serious harm, the scene of the accident must not be disturbed, unless it is to:

  • save a life or prevent suffering,
  • maintain access for essential services, e.g., electricity or gas; or
  • prevent serious damage or loss of property.

Worksafe will advise if the accident is to be investigated.

Supervisory persons who control places of work must take all practical steps to ensure the safety of persons in the place of work. They are responsible for the safe use, handling, transport and storage of all materials and substances used on the work site or in any other place of work.

 

12.1.2 Training 

Employers must ensure employees are either sufficiently experienced to do their work safely or are supervised by an experienced person. Employees must be adequately trained in the safe use of the equipment work-place, including protective clothing and equipment.
Employees and self-employed persons have a responsibility for their safety and health, and they must also ensure that their actions do not harm anyone else.
Self-employed persons have equal responsibilities as the employer to ensure that they are adequately trained and informed in all legal and practical matters regarding safety.

12.1.3 Working At Height 

Where a person may be at risk of an injury from a fall, suitable and safe means to prevent such a fall must be provided.

Safety fall protection systems include:

  1. The installation of an approved safety mesh over the total area to be clad (barrier).
  2. Edge protection for the total periphery of the area to be clad; including a scaffold or a guardrail fixed 1 m high to standards which includes a bottom and middle rail (barrier).
  3. Travel restriction consisting of an anchorage line and a safety belt.
  4. Fall arrest devices such as an individual safety harness.

Options (a) and (b) are the preferred methods of working safely at height.

Surfaces with fall-protection barriers (a) and (b) are regarded as an enclosed working environment and the roofer is free to work within this area.

A minimum safety standard for all workers on roof areas over 3 m high requires that:

  • A safety harness (fall-arrest system, option d) must be used for all areas that do not have a fall-protection barrier (a) and (b).
  • Travel restriction equipment (c) is required for all roof areas that do not have a fall-protection barrier or secure footing .

A fall protection barrier includes any barrier that will prevent a person from falling. It can be tile battens or roof framing at less than 500 mm centre to centre, a roof safety mesh or a work platform.

Edge protection can include scaffolding, scissor hoists or a guardrail system.

Permanent anchor points for a static line or other fall arrest device, must be installed in all buildings, exceeding 100 m², where the roof pitch exceeds 20°, or where maintenance is required for the servicing of air conditioning units and other roof mounted equipment.

 

12.1.3.1 Roof Edge Protection 

Where a person may fall more than 3 m, and there is no other means to prevent a fall, edge protection must be provided.
Edge protection is required to comply with AS-NZS 4994.1 general requirements and 4994.2 installation and dismantling.
People must be able to gain roof access without climbing over guardrails.
Access points must not undermine the integrity of the edge protection. Gates or other devices that guard openings must be self-closing and ladders must be placed as close as practicable to the entry and fully secured.

Main contractors and sub-contractors should liaise to provide an integrated fall protection method for all people working on a roof as a common safety system is more efficient than every subcontractor installing their own. There are many options for acceptable scaffolding and guardrail edge protection, some of which are shown in 12.1.3.1A Scaffolding and Guardrail Edge Protection.

 

This Code of Practice states ways of managing exposure to the risk of falling and encourages the use of an enclosed environment, so it is not possible to fall from or through the structure.

Personal fall protection systems are only useful in a limited range of applications on a roof and may add unnecessary risk to people working on a roof.

 

12.1.4 Residential And Light Commercial Roofing 

Worksafe is unable to give any dispensation to the Roofing Industry from the requirements of the Health and Safety in Employment Act 2015 and the Regulations of 1995.

Most residential buildings fall within a 3 m to 4 m height category and this height is measured from the edge of the soffit. Worksafe recognizes that experienced workers may work within these heights without the necessity of edge protection or harness surface, but certain conditions apply.

  • Workers should have undergone safety training.
  • Pitched roofs with a smooth surface less than or equal to 30°.
  • Pitched roofs with a textured surface less than or equal to 35°.

The intention of these conditions is to make the act of cladding the roof by skilled and trained workers, a separate act to that of working on a roof by other trades.

Textured surface roofs such as textured metal tiles, unglazed clay tiles, and asphalt shingles are regarded as providing an extra 5% secure footing, as opposed to a smooth surface. Smooth surface roofs include painted metal tiles, unpainted, and pre-painted profiled metal cladding.

Before any work is commenced, in all cases there is a requirement that the roofing contractor will have had sufficient safety training and education, that site hazard identification has been undertaken, and that a contractors safety policy is in place.

If there are individual site hazards, precautions need to be implemented at all heights. Hazards should be eliminated, isolated or minimised by the use of fall protection equipment.

Site hazards include:
  • Brittle roofing such as skylights, translucent, fibre cement or corroded sheets.
  • Slippery roof surfaces resulting from paint finishes, moss and lichen or dew and rain.
  • Roof pitches above 35°.
  • Roof projections such as pipework and flashings.
  • Any roof penetration larger than 600 mm by 600 mm.
  • Steeply sloping building sites.
  • Open foundations or drains.
  • Working within 2 m of any roof edge.
  • Wet or muddy ground conditions.
  • Rotten timber framing.
  • Fire damaged elements.
  • Plant and equipment.
  • Reinforcing starter bars.

A guideline for the prevention of falls is available from Worksafe.

 

12.1.5 Limitations Of Fall Arrest And Travel Restraint 

Whenever possible, an enclosed environment should be provided for roof installation and repair work so it is not possible to fall through or off the roof.

Harnesses are only appropriate for certain conditions, such as maintenance after the roof is completed or re-roofing work, and they are not satisfactory when snagging hazards are present.

The use of fall arrest harnesses or travel restraint systems is not the preferred alternative for people working on roofs, as these methods have limitations including the following:

  • Individual fall arrest anchors should have a capacity of at least 15 kN and roofs are generally not designed for such loadings; other anchorage points should withstand a load of 6 kN without failure.
  • The location of fall arrest anchorage points on roofs cannot be located directly above head height.
  • Fall arrest systems require a minimum of 5.5 m vertical clearance below the working surface to ensure the user does not hit the ground or another obstruction before the fall being arrested. This distance is required to be greater if static lines are used or ropes are slack.
  • In contrast to guardrail or scaffolding, fall arrest and travel restraint systems require a high level of training and supervision to ensure their safe use.
  • Ropes and lanyards can become tangled and snag on obstructions on the roof, particularly when a number of workers are located on the roof.
  • It can be difficult to have an effective rescue procedure, to ensure users are rescued before injury occurs, without putting other people at risk.
  • Persons suspended in harnesses after falling can lose consciousness or suffer modified cardiac rhythm if not rescued promptly and the rescue procedure should ensure persons can be rescued in less than 5 minutes.
Fall arrest systems must not be used unless specific training has been completed, that more than two people are located on site and any rescue procedure must not put other persons at risk.
The solo operation using fall arrest equipment is hazardous because there will be nobody to rescue a worker who could be unconscious and heavy. In some situations, at least two people may be required to safely rescue a person who has had a fall in a harness.
Systems that prevent a fall from occurring should be used in preference to fall arrest systems. Travel restraint systems are a higher order control in comparison to fall arrest systems because they prevent a fall actually occurring. However, travel restraint systems can be very difficult to set up and often impractical to use, particularly where corners of a roof require accessing or the roof has a number of penetrations.

 

Where access to the corner of a roof is required, workers must be attached to two or more sets of ropes and anchorages to prevent a fall from either edge of the roof. While accessing the anchorage points, the user must be restrained so that a fall cannot occur.

 

Persons using travel restraint systems require a high degree of training, as do persons using fall arrest systems, but the training for these systems differs.

When used in isolation, fall arrest and travel restraint systems are nearly always unsuitable control measures for a complete roof installation, and it is extremely difficult to set up a fall arrest system so that the user will not hit an obstruction before the fall being arrested.

 

The travel restraint system must prevent a person falling from the edge or through the roof. The use of travel restraint systems is not acceptable on fragile roofs such as plastic or asbestos cement roof cladding.
Fall arrest and travel restraint systems are generally only suitable for minor work such as:
  • roof inspection (not on fragile roofs);
  • installation of skylights and ventilation fixtures;
  • installation and removal of perimeter guardrail systems;
  • fitting ridge capping on metal roofs;
  • replacement of some isolated parts of the roof;
  • installations and removal of television aerials and other similar communication equipment; and
  • painting and cleaning;

 

12.1.6 Access 

 

Safe access should be provided to the working area at height by the provision of one of the following:
  • a permanent access platform or tower if the height is over 9 m;
  • a power-operated work platform, e.g., a cherry
    picker, scissor hoist or approved forklift truck; or
  • a ladder.
A ladder can only be used by one person at a time and must be:
  • a step ladder of maximum length 6 m;
  • a single ladder of maximum length 9 m; or
  • an extension ladder of maximum length 15 m.
To use a ladder safely, it must be:
  • set at an angle of 76° (4 up - 1 out);
  • secured against sliding top and bottom;
  • set on firm level ground; and
  • protruding by one metre higher than the roof;
  • used by no more than one person at a time.
 

12.1.7 Scaffoldings 

Scaffolding must comply with AS-NZS 1576 Scaffolding Standard.

Any person can erect scaffolding providing that it:

  • is less than 5 m high to the top of the working platform;
  • is erected in a tradesman like manner;
  • uses sound materials;
  • is properly braced and tied;
  • conforms with the scaffolding regulations;
  • conforms with AS/NZS 4576; and
  • conforms to the SARNZ guidelines.

Scaffolding greater than 5 m in height must be erected by a certified scaffolder and must be reported to the construction safety inspector at the nearest district office of Worksafe.

Working platforms more than 3 m high must be protected with guardrails, mid-rails and/or toeboards; however, it is recommended that all working platforms be so protected.

These requirements also apply to the erection, alteration or dismantling of all suspended scaffolds.

To prevent any inward or outward movement ties must be fixed to standards and be uniformly spaced vertically and horizontally over the face of the scaffolding.

Transverse diagonal bracing is required to stiffen the scaffold. It must be fixed to each end pair of standards and at not more than every tenth pair of standards. To resist movement due to wind, longitudinal diagonal bracing must be fixed to the face of the scaffold and at regular intervals along its length.

Ladders, steps or stairs must be securely fixed to the scaffolding, either internally or externally, to provide safe access.

 

12.1.8 Mobile Scaffolds 

Mobile scaffolds are freestanding scaffolds supported on wheels or castors and must only be used safely on firm level surfaces with the wheels effectively locked, braced, and stable against overturning.

Working platforms must be fully decked and provided with guardrails and toeboards as per fixed scaffolds .

 

12.1.9 Personal Safety 

Workers installing roof and wall cladding should take personal precautions to avoid damage to skin and eyes due to ultraviolet radiation.

Sunscreen or sunglasses should be used, particularly during the time of highest exposure (11 am to 2 pm ).

Ultraviolet radiation burning can be mistaken for windburn on windy days, and cloudy days can also produce severe burning. Some workers with a fair or sensitive skin., should always wear sunscreen protection when laying roof cladding. Glare from aluminium foil vapour barriers and from new metal roof and wall cladding can cause sunburn to some areas of the body not normally exposed to the sun.

Special care must be exercised when handling long-length sheeting, particularly in wet or windy conditions.

If the work is interrupted for any reason, or at the end of the workday, all loose sheeting and incomplete sections must be adequately secured against possible movement by wind.

Loose packs or loose sheets that have not been securely fastened must not be walked on.

When cutting metal with power equipment, eye protection must be used.

Gloves should be provided as personal protective equipment (PPE), and are an option for workers learning to handle sheet metal, however as experienced roofers often regard them as a hazard, they are not required unless expressly requested by the roofing supervisor or person in authority.

Reroofing presents a number of personal hazards. The condition of old metal or any other type of roof cladding cannot be ascertained until a detailed inspection is made. This should first be done from underneath, however, all translucent, asbestos, and fibre sheets should be regarded as brittle and safety precautions taken.

A booklet entitled 'Guidelines for the Management and removal of Asbestos' is available from Worksafe.

Translucent sheeting is not designed as a trafficable roof and it must not be assumed that a worker can stand anywhere on translucent sheeting.

Some owners paint over translucent sheets or skylights to remove glare, and this is not always obvious when viewed from the top of the roof. These sheets present a safety hazard, which should be investigated before re-roofing commences.

If the sheeting is too wide for a worker to cross safely, a short metal sheet should be temporarily secured over the translucent sheeting further than 2 m back from the edge of the roof.

Footwear should be in good condition, as worn footwear or loose or torn clothing can be a self-induced hazard, for which the worker himself is to blame. The weight should be evenly distributed on the soles of the feet without concentrating it on the toe or heel, and be placed in the pan of the roof cladding. When this is not possible the weight should be spread evenly over two ribs. See 12.6 Walking On Roofs.

Roof cladding is tested to a static load of 1.1 kN, which equals 112 kg and is meant to represent a worker carrying tools. It is therefore unlikely that a roof worker weighing more than 90 kg could avoid damaging a roof, because of the dynamic nature of the task.

Site supervisors should be made aware of the weight of everybody requiring access to the roof and should recognise that no two people should stand closer than 2 m from each other withing the same purlin spacing.

Tools should be hoisted up in a bucket when at the top of the ladder.

Workers should be aware of the added danger of climbing a ladder initially to secure it at the top . A second person should secure the ladder at the bottom while this is achieved.

 

A ladder that extends less than one metre above the roof gutter, does not provide sufficient security for access, and alternative arrangements must be made. Carrying equipment up a ladder must be limited to small items that still allow both hands to grip the rails.

 

Inspections of roofs are sometimes made by persons other than workers, such as owners, architects, and engineers who are not conversant with safety requirements for working at height. It is a 'Duty of Care' of the Supervisor or person in authority to point out the specific hazards on the site, and to provide the safety equipment necessary to carry out their required tasks.

Workers taking medication without notification or who have ingested alcohol or other drugs are at risk when working at height. Because their actions place other workers at risk as their balance and judgment may be impaired, this is sufficient cause to dismiss a worker from the workplace or worksite.

 

12.1.10 Safety Mesh 

 

Safety mesh, when designed and installed to comply with the requirements of the Health and Safety in Employment Act 1992 and the Regulations of 1995, is accepted as a fall protection barrier. It provides a double role, both for safety and as a support for underlay or insulation depend ing ent on its position within the structure.

The NZBC durability requirement for safety mesh is 50 years and covers the total safety mesh system, including fastenings.

To comply with AS/NZS 4389:1996 safety mesh is required to be constructed from galvanised welded steel wire with a minimum diameter of 2 mm and a minimum tensile strength of 450 MPa. The grid spacing must be 150 mm longitudinally and 300 mm transversely, with a 5 mm leeway in either direction. Other materials are deemed to comply if they pass the test requirements of the standard.

In corrosive, severe marine and industrial atmospheres, safety mesh must be protected by the application of a U.V. stabilized protective coating as required by AS 2312: 2002 and the mesh must be free of sharp edges and burrs that may cause injury to the handler or installer.

The mesh joins and the connections to roof members must withstand the same point loads as the roof cladding, and the rectangular apertures resulting from the lapping and joining of longitudinal strands must have the same orientation and must not be larger than those of the mesh.

The mesh must withstand an impact test. The test load sandbag must not penetrate the mesh during or after impact and a 350 mm sphere must not pass through any part of the test specimen.

The safety mesh must be fitted under the roof sheeting so that it rests upon the purlins, battens, or rafters and so that the transverse wires are closest to the roof cladding. When installing safety mesh or hexagonal wire netting, workers must use scaffolding or fall protection equipment as described in 12.1.3 Working At Height.

One acceptable fixing method is first to position the rolls of mesh on mobile or other suitable scaffolds either side of the roof and then to take a continuous rope across the ridge to pull the mesh on top of the purlins across the roof.

The mesh must not be used as a work platform and is not safe until it is tied-off at each end as described and shown in 14.1.10 Timber Fixing and 12.1.11 Steel Fixing.

The longitudinal wires, parallel to the direction of the corrugations of the roof sheeting, must be on top of the purlins, and the transverse wires at right angles to the direction of the corrugations must be on top of the longitudinal wires.

Protection must be provided to GRP, light gauge or soft metal roof cladding between the mesh and the cladding to avoid marking or damage by expansion or by walking traffic.

The joins between adjacent lengths of mesh must be side lapped by one mesh spacing and if the purlin spacing exceeds 1.7 m intermediate tying, twitching or stapling with 2 mm wire is required.

Safety mesh is accepted as a fall protection barrier if it is constructed :

  • of galvanised welded steel wire with a minimum diameter of 2 mm;
  • using wire strength of 450 Mpa;
  • with wires spaced 150 mm longitudinally and 300 mm transversely; and
  • with the transverse wires closest to the roof cladding

Safety mesh must be tied off to purlins as shown below in 14.1.10 Timber Fixing and 12.1.11 Steel Fixing.

 

12.1.11 Steel Fixing 

 

When attached to metal purlins, the longitudinal wires of the safety mesh must be passed through a hole drilled in the top of the purlin and tied off with at least four full turns around the same wire. See 12.1.11A Longitudinal Wires Run Through Steel Purlin.
 

Alternatively the longitudinal wires of the safety mesh must be passed once completely around the purlin, the tail of each wire being twisted four times around the main portion of the same wire. See 12.1.11B Longitudinal Wires Wrapped around Steel Purlin
 

Safety mesh must be tied off as shown below.

 

 

 

 

 

 

 

 

12.1.12 Joining Safety Mesh 

When joining rolls or sections of safety mesh the two transverse wires must be placed together and the longitudinaltail wires must be twisted around each other. One longitudinal tail wire must be twisted four times around the main portion of the same wire. The other longitudinal tail wire must be twisted once around the main portion of the same wire and then four times around the two transverse wires.