Is it acceptable to use a handrail to interconnect a lightening protection system

Question

At one of our Tower blocks in London we came across this on the roof, I don't know a lot about LPS so was after some advice or any thoughts.

Also as this chimney is higher than the rail wouldn't it need to be connected to the LP system ?

Any advice on reference books or sites would be most welcome, I will be looking at doing a training course on the subject. 
 Thank you in advance for any help offered.

mapj1 · Accepted Answer

It does not sound ideal, but as you say we cannot see it from here. Personally I don't think it is especially dangerous, so long as all the connections are solid, and no-one goes on the roof in thunderstorms and the rail is not connected to other things -or if it is, then to ensure it cannot pass high a high voltage into the building by some other metallic connection such as to building steel. 
 It is also worth asking what the antennas connect to, and what would happen if those coax cables shot up by a few hundred kV for a little while... 
 I presume the system is inspected periodically for insurance reasons. I suggest, that the next time this occurs, you ask the person doing the inspection for a professional opinion when it is in front of him/her. 
 Mike.

chrisbryant · Answer

Hello Daniel, 
 Handrail can be used as long as it meets the minimum thickness requirements - likely it will. 
 The metal flue should be bonded if it can be confirmed it can carry the expected lightning current, if not it should be included within the protection system. 
 BS 62305-3 gives the minimum material thicknesses, but as Mike has said, Furse do some good guides to BS 62305 for free.

Is it acceptable to use a handrail to interconnect a lightening protection system

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