Some good points here. - I will check up on the crane's paper on fluid flow (I presume that it is the "Crane Technical Paper No. 410" - found following a web search), and Miller's Measurement Handbook.
martindup - I would be interested in seeing the spread sheet - I can be mailed at...
Thanks all for your comments:
1 TD2K - How did you calculate that? what is the correct formula to use?
2 EGT01 - This is a client request. I'll try and find out, but I can suggest that the main pressure of 180 psi (12.4 bar) results in a too high a reaction force on the fire fighting hoses.
Are you able to advise the size of an orifice plate that will be fitted into a fire hydrant main to give a pressure drop, (when 1 hydrant is running at full bore) from 180 psi to 55psi.
The main is Thin Wall Stainless Steel line with an internal diameter of 150mm, and a fire hydrant connection...
In the UK the British Standard 5295, published in 1989, is also used to classify cleanrooms. This standard is about to be superseded by BS EN ISO 14644-1.
In a temporate climate the intake dampers are often used as part of the frost protection system, and shut when the ahu is inoperative.
There are usually separate FP systems in place to protect against freezing coils, but in the event of failure of these, a low temperature detector downstream...