BS9990 - 2006 - Non-automatic firefighting systems in buildings

[Jon Barrett]

This BS recommends that 'Isolating valves should be incorporated in the system (Fire Mains) at intervals not exceeding 10m so that sections of the fire main can be isolated to enable repairs to be carried out'.

This seems excessive - does anyone know whether this may be a typo error and should be 100m?

Thanks,

Jon

[kurnal]

After reading your post I looked at a draft copy of the BS in which no dimension between valves is specified. Havn't got the final document.
It doesn't make sense does it. Installation of too many isolating valves has a negative effect as well as there is more to go wrong and more potential for error and failure.

Which section of the standard have they put  it in? In the draft the reference to isolating valves was under 4.1 general design considerations (for all systems) - but I assume they are referring to wet mains - there would be no point at all on a dry riser!

[Jon Barrett]

The final document has the reference to isolation valves in clause 4.1 - 'Design Considerations' under the section 'Fire Mains'. Like you, I can only see that this is of benefit on wet mains.

I can also see why you would want isolation points on large runs of mains, for example a ring main serving a shopping centre. And a reasonable distance would be 100m, not every 10m!

Perhaps I need to contact BSI.