The provision of a permanent safe working environment throughout the roof installation (and for future maintenance work) can be achieved by using the Safety Mesh system over the entire roof plane.
Safety Mesh consists of 2mm galvanised wire with a tensile strength exceeding 450 MPa. The longitudinal wires are spaced at 150mm centres with crosswires spaced at 300mm centres. The rolls are 2100mm wide and are supplied in standard 50m rolls.
Safety Mesh complies with the “Safety Mesh requirements in the Approved Code of Practice for Safety in Working at Heights”, as published by the Occupational Safety and Health Service of the Labour Department. Safety Mesh, securely fastened over the entire roof plane, eliminates the need to use harnesses, static lines, inertia reels or other safety equipment, except when working closer than 2m to the edge of the roof.
Safety Mesh has passed dynamic and static tests as required by AS/NZS 4389-1996. The dynamic test has a 1500mm x 350mm, 165kg sand bag dropped from a height of 1400mm onto the mesh. The static test has a 350mm diameter probe pressed into the mesh with a force of 50 Newtons. To comply the sand bag or probe must not penetrate the mesh.
Limitations On Use
- Do not use Safety Mesh for access or as a working platform.
- Workers should avoid walking or standing on Safety Mesh.
- It is not practicable to allow Safety Mesh to “sag” between purlins to accommodate insulation.
- For corrosive environments specifiers should consider PVC coated Safety Mesh.
Safety Mesh complies with the following standards for mesh:
AS/NZS 4389-1996, Safety Mesh.
Architects or design engineers should specify Safety Mesh at the initial stage of any commercial or industrial project. For corrosive environments PVC coated Safety Mesh can be specified, refer Dimond for details.
Installation of Safety Mesh
The fixing procedure is incorporated in a pamphlet included in every roll of Safety Mesh. Other pertinent installation details follow:
- Take a continuous rope across the ridge; for this first pass workers MUST use appropriate fall protection equipment.
- Position the rolls of mesh on mobile scaffolds either side of the roof and use the continuous rope to pull the mesh across the ridge.
- Wires parallel to the direction of the corrugation of the sheeting (longitudinal wires) should be in contact with the tops of the purlins. Wires at right angles to the direction of the corrugations (transverse wires) shall be on top of the longitudinal wires.
- Tie off to an anchor point the longitudinal wires of each “run” of mesh in accordance with one of the approved methods described in the pamphlet included in the roll. NB: The mesh is not safe until it is tied-off at each end. Anchor points can be 3mm diameter holes drilled into the steel purlin or 40mm long x 3.5mm diameter staples for timber purlins.
- Side laps of the mesh MUST be lapped by one mesh spacing (150mm). If the purlin spacing is greater than 1700mm the side lap is to be twitched between purlins.
- All wire joints MUST be twisted four times.
- End joins should be avoided, but can be used provided the procedure in the Safety Mesh pamphlet is carefully followed.