Posted By Richard McLellan We have built a scaffold round an exhaust stack in order to strip off old insulation and apply new. There is a gap between the scaffold boards and the stack (150 - 200 mm) to allow the insulation to be removed. My concern is that when the insulation is removed the gap becomes bigger - perhaps enough for a man to fall through. I want to specify that fall arrest equipment is worn when the gap is big enough to create a hazard of falling. How big is big enough? I could measure the diameter of all my insulators, but perhaps there is statutory guidance on how big a hole is permitted.

Posted By Ron Hunter I've had dealings with Inspectors who would suggest the gap is already too big, i.e. large enough for someone to fall down & (say) break a leg. Would it be possible to design,make & fit "hop-up" boards to close both the original and post-strip gaps, these only being removed when the area is being worked on? Would our wider discussion on WAHR suggest taking down the stack and re-erecting it after refurbishment?!!!

Posted By Frank Hallett Good evening Richard You need to obtain a copy of the Work at Height Regs [free download from HSE & HMSO - no ACoP] and ensure that your staging complies with Schedules 1 & 2 if at all possible. From your description of the activity, you won't be able to comply fully, so you will have to give consideration to Shedules 4 &/or 5 as well. Good luck Frank Hallett

Posted By Frank Hallett Ok Richard, it's always difficult to determine just what an enquirer may know [and understand] from the initial question, my apologies for telling you something that you alrady knew. As you have the WaH Regs to hand, you will also be aware that there is a requirement for working platforms that doesn't just address the ability for a person to fall through but also specifies the allowable dimensions of any allowable gaps. I appreciate that my next comments may seem over-kill [sorry for the pun everyone], but the ability of HSE to impose draconian measures until you have satisfied their perception of what may be required is over-riding - especially in the kind of job you describe. As I see it, you have two workable alternatives, which may need to be used in conjunction with each other. First, consider the provision of a secondary, lower platform or net that is designed and positioned to close all gaps through which anything, including people, may fall. This will satisfy the hierarchy principles for "Collective" protection at the highest [sorry - unintentional pun again] level of reasonably practicable. If a potential remains for persons to be able to fall through that you identify as requiring further measures, then it would probably be appropriate to provide individual fall protection that prevents the fall rather than mitigates the fall. Of course, your working platform will now have to be designed to withstand the loading of restraining a falling body and the operatives must still be able to do the job! Hope that this alittle more useful than yesterday. Frank Hallett

Posted By Richard McLellan Thanks again for your input gents. Frank, I'm sorry if I replied a litte snappily, you have been understanding and helpful. The risks of handling the stainless sheet cladding through an inner set of handrails also have to be considered. The cladding sheets transit the scaffold lifts so an 'underdeck' would not be practical. I think we will specify fall arrest equipment. We have a full emergency response team and I spent much of today putting together the rescue plan for a casualty on the scaffold. Read as I might, I cannot find reference to dimensions of gaps in decking in the WAH regs, just sizes of toeboards and handrails. I was interested to hear of the brickie falling through 260 mm gap. We feed our men better in the offshore environment (no brickies though). I will see if it is practicable to restrict the maximum gap to 250mm or less. Any advance on 250 mm?

Posted By Richard Webber Hi Richard, Would a pragmatic solution be to ask your Scaffolder to equip his scaffold with telescopic transoms? They would allow you to vary the distance between the inner board and the face of the building. As you strip off the old insulation, or work on the face of the stack, your Scaffolders follow and open or close the gap. You should close the resulting gap as soon as reasonably practicable and remind all of the prevailing and recurring hazard. Richard