Transition and Beyond
In part 1 we examined the various methods of gaining access up the side of a building in order to reach the roof. I will now go on to discuss the transition onto the roof and further roof access. Just as in part 1 we are considering predominately non-domestic buildings. This blog does not cover slate roofs or other steep roofs or cement roofs.
It is important that when stepping onto the roof you are stepping onto a level, non-slip, non-fragile surface. This is especially true when transferring from a ladder as this is often the most perilous part of accessing a roof. Levelled walkways can be fitted to almost any roof type. As well providing a safe landing they also protect the roof from damage from foot traffic. Consideration should be given to extending the walkway to key areas.
Ideally, before stepping off a ladder you will be connected to an anchor point via a shock absorbing lanyard. Such an anchor point is provided at the top of out vertical wire systems extension post.
If you are using a double lanyard you are then able to transfer to a roof mounted anchor such as a roof horizontal roof safety line whilst maintaining continuous connection.
Ideally guard rail would be provided around the entire perimeter of a roof. If this is cost prohibitive, it may be possible to install roof guard rail just around the access point to provide increased safety.
When having a horizontal roof safety line installed it is important to be very clear on your objective. Where do you want to reach, how many people need to get there and what kind of lanyard or rope will you connect to it with? Consultation with a professional is important at this stage.
Ideally the system will be designed so that a fall is not possible. However, this cannot always be achieved. A particular hazard that is often present is that of fragile roof lights. Roof lights are very easy to forget about until you are standing on top of them. This is especially true of the roof lights on metal profile roofs. Whilst more modern buildings will have installed class B non-fragile roof lights this is only of limited reassurance. The test for non-fragility in roof lights is to simply drop just 45kg’s of weight (I believe a sandbag is typically used) from a height of 1.2m. It only has to take this impact and survive once to be classed as ‘non-fragile class C’. If the roof light survives this twice it gains the status of ‘non-fragile class B’. 45kg’s from a height of 1.2m does not seem to build in much safety margin! In addition to this, roof lights could be subject to accidental loads over time which could render them ‘fragile’. They must be properly installed in the first place with the correct number of tech screws or their performance may not be the same as when they were tested. Over time all roof lights will become more fragile due to deterioration from exposure to UV light. For all the above reasons it is wise to consider your roof lights to be fragile.
Could a fall arrest system on your roof allow an operative to fall through a roof light? If someone did fall through a roof light on a fall arrest system, how far would they go? The answer surprises some people. By the time the roof safety line has deflected and the shock absorber in the lanyard deployed, an operative could easily end up with feet dangling 5.5m or more below roof level. An additional 1m safety margin should be allowed for so typically 6.5m of clearance below a fragile surface is needed for a fall arrest system to be considered effective.
The average warehouse or factory will have racking, machines, beams and mezzanine floors all denying us the fall clearance we need to effectively arrest a fall. Where fall clearance is not available below a roof light it should be covered. This doesn’t have to deny you light. There are very good roof light covers available that still let through 90% of the light.
Even where there is adequate fall clearance below a roof light, by providing a protective cover safety is greatly improved.
It is imperative that all fall arrest systems are tested and inspected at least annually, along with your working at height PPE.
In part 3, I will discuss the importance of training and having a rescue procedure in place. Follow me to ensure you don’t miss it!