Sprinklers: All-New Versus Modifying Existing?

5/28/2019

A project we're working on has an existing basement area that is broken up into many small existing rooms. Each room has varying ceiling heights and different grid directions.

The remodel that is going to be done will change all of these small spaces into three areas with a consistent new ceiling height that is about the average height of the existing ceilings.

If you are the engineer preparing bid documents in a scenario like this, would you call out for full pipe replacement, or only to modify the existing branch lines?

I would be interested in how others approach this issue prior to bid.

On one hand, modifying the existing system has the potential to save a significant amount of pipe, but could require some large stretches be raised to accommodate new ceilings and would require a good handful of labor to relocate sprinklers.

On the other hand, while an all-new pipe arrangement may cost more in material, it would be better able to coordinate with new HVAC ductwork and ceilings in the space and could possibly reduce the labor time with a pre-fabricated install.

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2 Comments

Dan Wilder

5/28/2019 08:56:07 am

You will never match or beat labor install by removing and reinstalling an entire system vs changing a couple branch line heights. This will also add coordination over an entire area to the mix vs a couple small sections. Remember that demo/haul off still costs money and you may have access issues for the staging of the new piping in full lengths in a basement situation.

The only justification for a full pipe replacement is if a significant degradation of the pipe interior or a water supply/hydraulics issue exists.

As a contractor, modify only what is required and leave the rest of the existing piping alone. If the HVAC contractor has to think a bit for his install, that is still one less party costing the owner money. If there are routing issues, leave some allowances in the contract for those reroutes.

Bruce Seiler

5/28/2019 10:27:15 am

This is always a tricky situation as each scenario offers different challenges. It seems you are going to have fewer sprinkler heads being installed than currently installed due to the smaller rooms becoming larger rooms. Depending on the layout of the rooms and existing system, relocating the old pipe could be costly due to unused outlets or pipe.

As a contractor who bids projects like these all the time, this tends to be vague. The documents usually state something along the lines of utilize existing system and relocate sprinkler heads as required. Raise existing branch lines for higher ceiling. This usually causes the estimates to be at different ends of the spectrum with different contractors figuring differing amounts of work.

Ultimately, if the existing pipe is in good condition, the best bet is re-work the existing pipe to the new ceiling, however it could be left up to the contractor to provide new pipe if costs for demo, removal and coordination are included.

The contractor needs to draw up and recalculate the system in either case due to occupancy change. Or, at least they should per NFPA 13 requirements.

In short, I agree existing pipe should remain unless it is deemed in poor condition and would benefit from replacement. Let the contractor decide what is more cost effective in their pricing, but make sure they have included all options in their price prior to accepting the terms. You may have to do some leg work on providing existing elevations of the pipe, which would help get the costs more inline.

Sprinklers: All-New Versus Modifying Existing?

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