Fire Pump Calc

Did you not hear what happened to the Twin Towers?

Thanks JohnDG, that would be in line with duplicating capacity. Is there a revision of the IFC/IBC regarding this?

This question can only be answered by a Civil Engineer.

That engineer will be familiar with the local codes and requirements.

Since we don't even know what country you are in, it is foolish to expect an intelligent answer to such a broad question.

You are not considering using one system to protect both buildings, right?

You DO have an engineer working on this project, don't you???????

Lyn, yes we have a civil engineer working and also others. Original buliding is protected according local codes and requirements, that is fully sprinklered and fire pump and tank. New building shall be identical. Local codes do not call for addittional pump and water capacity if building is same owner (condominium like). I personally think it would be wise to assume new building would impose addittional concurrent hazard.

To hell with local codes, treat it as a separate building,use all the latest safety equipment, and personally on a 25 story I'd like to see at least two storage tanks in the building,one at the top & one midway so that your not relying on power pumps that may fail.contry to the film companies, not all sprinklers come on at once like they do in films, only the ones directly in the field of the fire, so you're not dumping tons of water all at once, so a steady flow is whats needed, the initial pressure is by compressed air on the tank, which gives time for fire services to hook up and start replenishing the water and pressure in the tanks.

Bazzer.

Thanks Bazzer Englander for your comments. We are already proposing a booster pump midway to the building top to ease the burden on the main pump located in the basement where the firewater tank is located. Both buildings are designed with state of the art fire protection technology and will propose a pump/controller scheme for each building with a backup transfer manifold in the event of maintenance/failure of one of the pumps.

Your system overall must be designed to supply adequate water to the largest hazard zone at the most remote hydraulic location. One pump connected to two buildings is a single system.

If the water supply line from the pump to the new building is the same length, and the sprinkler system design for the new building is a mirror image, you should not even need to provide new design calculations.

The only possible fly in the ointment is your local code officials. If they allow a single pump to supply both buildings (most will), you are on solid ground in terms of design.

On the other hand, as a professional, I would recommend against such a design if the buildings were within 100 feet of each other. The cost of an additional pump will be chump change compared to the building.

Thanks WJMFIRE, you are in line with out thinking, excess cost for additional pump is nics compared to new building TIC.

I belong to a forum of Building Code officials, and I took the liberty of asking your question there. The consensus (so far) is that it is probably allowable to use only one pump, but this guy makes a very good observation:

"The existing fire pump could serve both buildings if properly sized. However, you need some agreements and easements in place so that if one... building is sold, that the fire pump in the existing building will continue to serve it."

Thanks Doorman, good comment to include in owner documents.

Another reason to have two pumps, If you sell one building and the new owner wants to flatten it you've then got to start retro fitting a new pump which is always more expensive, with two pumps there is backup, & lets face it sods law says when you most need it it breaks down.

Bazzer