I've been seven years in the chair, and the most thankless job I encounter on every project is - reviewing the site utility plan and picking it apart.

I've now made my own rule that I will only point the civil engineer's mistakes once, early in the project, and when it comes time to stack the riser, pressure test, etc, all I can say is "I pointed that out to you on Aug 11 2020 email."

Am I going about this the wrong way? SHould I even be investing energy into correcting the engineer with the stamp?

Recent example is a two story building with concrete tees. We're adding third and fourth floors from new structural members. The underground man took the site utility and started digging. Check valve was exposed above ground (supposed to be in pit) and the FDC was connected to the underground on the system side of the backflow preventer. Now he has to dig it up, cap the tee after the backflow preventer, and run it around and inside the building. The job requires a small pump (CL1 manual wet standpipe), and the underground man wasn't happy. All I was doing was point out wrong installations before it was too late.

I'm always left thinking, "this isn't even in my scope of work, but it affects everything downstream."

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I'm looking for guidance on protecting a bag house/dust collector at a sawmill facility.

The unit comes with outlets attached for nozzles/sprinklers. Some of the existing ones at the facility are protected with anit-freeze systems, some with dry systems. 

Is there a reason you would need to use anti-freeze in lieu of a dry system for this application?

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Are there ever scenarios where fire sprinkler branch pipe would not be perpendicular to structure?

As I understand it, running perpendicular to structure affords installers the most flexibility in hanging locations and avoids having to use trapeze supports throughout a project where support from the floor/roof assembly isn't possible. 

Just curious if branch pipe perpendicular to structure is an always scenario or just a prevailing scenario. Thanks in advance, appreciate your all's input.

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I recently acquired a project where I'm replacing all sprinkler in a residential home. Apparently the original sprinkler heads were the OMEGA that were recalled some years ago on.

These specific heads had a K=factor of 3.9 and although I have found only one direct replacement with the 3.9 K=factor, they are not cheap!

My question is what would be an alternative replacement to these k-3.9 Omegas, and would replacements need to be the same k-factor?

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I'm hoping somebody can point me in the right direction on this. I'm doing a VA Clinic in California. Somehow I didn't notice that there were OSHPD requirements but I am having trouble finding information that clearly identifies the different hanging and bracing requirements that we'd need to abide by.

I know in the past we had to use clevis hangers, rod stiffeners, use solid strut for all seismic bracing etc, but back then I was a fitter and it was on my plans already.

Where is there guidance on the acceptable hanging types to meet OSHPD requirements?

I appreciate your help.

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Any thoughts or experience in system life expectancy for dry sprinkler systems with galvanized versus black steel pipe, and compressed air versus nitrogen?

Our firm (MEP/FP consultants) typically recommends nitrogen and galvanized pipe for dry sprinkler systems, and we often get the value engineer requests to accepts compressed air and/or black steel.

Any studies or data that support your experience? Approximate cost savings you might expect from each?

Thanks in advance!

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It's clear that gridded dry systems are no longer allowed by NFPA 13 (for the last 30-40 years or so), but what about a looped dry system?

If I understand it correctly, gridded dry systems are not allowed because water delivery time is typically hindered, and gridded systems may not be set up to drain particularly well.

Is that true of looped dry systems? If the total volume of a looped dry system is small (200-500 gallons), and water delivery time is not an issue, I could see major advantages to looping a dry system for areas like parking garages or attics. Thanks in advance.

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What would be reasons to use a hydraulic design point other than the lowest flow rate just over 1,500 sqft of remote area?

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Some fire pump assemblies have closed-test loops. When we circulate water through this closed test loop, why does the suction pressure not increase?

I'd be interested in understanding the physics of the situation a little better here.

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How can we prevent the formation of algae or microorganisms in water storage tanks for fire protection due to the water being stagnant?

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I was looking through the International Building Code and have not found a requirement for a fire sprinkler riser room to be enclosed by a fire-rated wall.

Are there any requirements other than clearances to service the equipment for this room?

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​Will high intensity sound, 200 dBP, activate either glass bulb or fusible link sprinklers?

Is there any documentation that supports either way?

Thank you.

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We have a lot line sprinkler installation with sprinkler piping being recessed in a furred out wall. We are concerned about pipe freeze ups.

Since we are connected to the existing system that serves the entire floor it would not be feasible to do a dry pipe system or add anti freeze.

Does anyone have a good calculation to determine if the piping will freeze in the wall cavity?

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I have two questions on projects in areas that are seismic regions D or more restrictive and flood prone/high water table:

NFPA 13 (2016) Section 9.3.4.3 where clearance is provided by a pipe sleeve, 4 in. pipe & larger require 4 in. larger pipe sleeve. So if we are providing a below grade wall or floor penetration, that experiences high water tables and flooding.

What are the most common practices to prevent ground water intrusion through the pipe sleeve?

NFPA 13 Section 9.3.4.8 states - where required, the clearance shall be filled with flexible material that is compatible with the piping material. Is this most likely a water proofing or rated caulk?

My original thoughts lead me to something like a Metraflex Sliding MetraSeal or any pipe sleeve seal on the market, but think that would go against the internal pipe sleeve clearance requirements. Any suggestions on best practices?

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I'm putting together design-build requirements for a new single-story construction building. The flow test pressure is borderline in my opinion so I'll be calling for a fire pump.

When is a water storage tank required with a pump?

I don't think the system needs one, but I just want to be sure.

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Any good software resources out there for predicting fire alarm signal audibility across walls and doors based on their attenuation values and ambient sound pressure?

​Editors Note: Another fire alarm question today, love it. Keep 'em coming! You can post any fire protection-related question using the "Submit Your Question" link below at any time.

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As a consultant, what level of detail do you go into for the line voltage (120v) fire alarm plans and wiring?

The line voltage is affected by loads / fuse sizes and affects the disconnect switch size. I'm wondering about the level of detail that an engineer should be showing versus leaving the sizing to the fire alarm and electrical contractors based on their specific system layout requirements.

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We have an auditorium project with a walkway that is constructed beside the seating area at the first and second levels. The second level has been provided with beam-type smoke detectors. 

There is a suspended ceiling below the walkway which is approximately 6-feet (2 m) from the wall. Do we need smoke detectors below this suspended ceiling?

The design currently has smoke detectors only inside ceiling void spaces below the walkway - is this in compliance with NFPA 72?

The fire alarm contractor is arguing that if a fire originates at the floor level below this walkway, it will be easily detected by the beam detector at the second level due to the smoke buoyancy. 
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Do you know of any specific guidelines for space around a fire pump skid to leave in a fire pump room?

I have always worked off the notion of "enough clearance to get around and work on a pump" but that is very subjective. So, I have a self-imposed 3-foot clearance around the edges of a skid. 

Is there anything more specific in generally adopted codes or standards?

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​We're always thankful for the expertise and input shared with this collaborative community. The wide range of voices (from designers to AHJs, inspectors and engineers) is great. Here's a thank you to all our contributors, especially our Top Ten for November 2020: