http://www.hse.gov.uk/co...tytopics/welfare.htm#toi http://www.hse.gov.uk/pubns/indg293.pdf No dimensions I'm afraid but they must be suitable and sufficient. I suspect the ones you have inherited are not due to the size, if nothing else ?

Yep, "suitability" is exactly what I'm investigating. 1500mm comes from Building Standards (Scottish equivalent of the Regs - with the proviso that this isn't something I'm familiar with, just having researched this topic), or at least that's roughly the resulting figure with the mandated 450mm area clear of door swing, but that's larger than in many sites I've been on, so I'm really asking what others use, and how they came to that decision. 1500mm would mean a significantly larger cost to us than, say 1300mm (which 'feels' ok) as it could not be accommodated by refurbishment. Much appreciated, thanks!

where possible go for the biggest that U can get as B-Standards / Building regs HSE guides etc. are only suitable for certain situations e.g. they do not account for weather, PPE , dirt, size of user, location, environment etc. and U need to have an idea of just how big your users are 'likely' to be e.g. one job I was on the only way some of the guys could use the toilets was to use the disabled toilets as the group consisted of 20 men the shortest [after me] of which was over 6 ft and large! additionally another job i was on [BBC work] consisted mainly of people that were all under 5ft! so two sets of loo's were needed use the risk assessment process as well as other areas to present your case noting that those office bods who issue budgets for such things have no idea what happens on site in most cases but they all have warm, clean and cushy toilets readily to hand for themselves in the 1960's U used to go into a corner and pee as there was little option nor welfare on small jobs especially and ~50 years later U are having to do the same - this makes me feel ashamed