Maintenance of historic fire rising main

[kurnal]

A historic mill of 4 floors, top storey height 20m, has  brick walls, brick floors on cast iron columns and beams and was erected in 1906. It has rising wet mains in each stair. The rising main is directly connected to the towns mains and the gauge standing pressure is 50psi- ie 3.3Bar at ground floor. No facilities for fire service to supplement the supply. I assume it will be 1.3 Bar at top floor level and neither use nor ornament for fire fightng.

Article 38 requires the maintenance of such facilities if they have been provided under the requirements of Building Regulations or any other enactment.  

Does anybody know if these mains would have been originally provided under an enactment ( Mill is in Oldham and is used as a warehouse)?

I take the view that if the main was installed as an insurance company requirement rather than a legal requirement it may be legally removed. The insurers are not interested either way.

I am trying to persuade the owner to convert it to a dry riser but they are reluctant to do anything unless there is a legal requirement. No significant changes have been made to the building in recent times that would enable application of approved document B5.

[John Webb]

Clearly the pressure at top floor level is inadequate for fire-fighting jets. (I wonder what the inlet pressure was when they were first installed?)
I wonder if they would be acceptable now to the water supplying company? Is the local water company aware of these wet risers? Do they feed hosereels? Do they go through a meter somewhere? Do they have isolating or non-return valves? I hope you get the drift of my thoughts - it may be possible that they contravene more recent legislative requirements regarding connection to the water supply and prevention of contamination of the same.

[kurnal]

No John the public main feeding the site is 150mm and this installation is teed off it without any non return valves as far as I can see. Theres just a big gate valve at the inlet and a gauge above the valve. No other equipment is fed off this dedicated pipe.
There is clearly a potential for back feed and contamination if someone opens a valve somewhere near the top!
I wonder if the water bylaws are retrospective? Clearly the thing serves no useful purpose from a fire point of view but before suggesting its removal I need to make sure of the legal background - it would be easy if my client was prepared to improve the situation by installing a dry riser but they dont want to know and the insurers arent interested. ( The mill has a  good sprinkler system fed from new pump house and static tanks)

[John Webb]

If the 150mm main is also the feed to the static tanks for the sprinklers, could one argue that it ought not to be used for supplying wet risers as well on the grounds that this would upset the supply to the sprinklers?
Bearing in mind there is a full sprinkler system installed, I'd be inclined not to worry too much about having dry risers - hopefully the sprinklers will keep a fire in check to the extent that only a hose-reel jet will be needed for the final damping down. A problem arises if the sprinkler system has to be completely shut down for any reason - the insurers may get concerned at that if there is no alternative?

[Fishy]

If it's safety kit to remove it you have to demonstrate that it has no safety benefit at all.  If its presence could reduce risk (by even a small amount) it has to stay, and be maintained.