Having been involved in Reading Phab for many years, this problem of
grab-rails has been encountered a number of times. Whilst the grab-rail
itself may well be designed to withstand the weight and load applied by
individuals, (Though I am not aware of what the specific figures are!) on
most occasions, the cause of the problem has turned out to be due to the
less than satisfactory mounting or fixing bolts used to hold the grab-rail
in place. 

I'd cite the following as examples; 
a] Plastic 'Rawlplugs' being used where metal versions should have been used.
b] Rails being fitted to a surface (such as plasterboard walls) where behind
the surface, a wooden battern for it to be attached to, wasn't located.
c] A minibus where the rail was pinned to the frame of the vehicle and a
reinforced 'plate' to take the load, was not welded to the surface to take
and spread the load, so that the fixings were eventually pulled out of the
the sheet-metal frame. 

In short, these problems arose due to failings in the type of fixing device
employed, rather than the actual rail. - Diameter of heads of bolts/screws
not wide and/or long enough - Washer/s to spread the load over a wider area
not used - No check was made regarding if a supporting or bracing member was
located directly behind the the wall surface the fixing was applied to (Can
be checked out with a battern locator available from DIY stores) - or the
fixing system (very common this one!) was plastic wall plugs, rather than
the more expensive expanding metal fixing devices. (Many rail-makers seem to
 presume people will use the rail to steady their balance, rather than pull
themselves up or/and a means of support capable of withstanding the load of
an individual (possibly of less than 14 stone) suspending themselves whilst
manovering into position. I have seen rails 'designed' for people weighing
in excess of 14 stone, supplied with plastic 'Rawlplugs' that use less than
5mm diameter screws which are less than 20mm long .... Utterly inadequate!

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