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:

We are in a fire sprinkler retrofit and we have steel joists and decking throughout the building, with mostly masonry block walls. It's a single-story structure.

Where there are doors, however, there is wood framing above the grid ceiling.

How much wood constitutes an issue requiring fire sprinklers above the ceiling?

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I have a question about protection of sprinklers in windows specifically for a connection of a basement parking garage and a first level mall commercial space.

NFPA 101 accepts that there is a connection between both occupancies, but there must be compartmentalization of 3-hours without automatic sprinklers and 2-hours with automatic sprinklers. In this case, we have an escalator from the basement up to level 1, as shown below:

Can we consider this to be compartmentalized with glass and sprinklers on both sides of the glass?

Do the access doors have to be 1-1/2 hour, our could they not have any fire resistance if I have sprinklers on both sides?

This project is under NFPA 101 (specifically Table 6.1.14.4.1 for separation between occupancies), NFPA 5000, and NFPA 13 (9.3.5/19.4.3 for sprinkler protection of windows).

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We have a large production facility where there is an isolated small room that is remote from the sprinkler riser room. This small room houses tools and other equipment which the owner sees as valuable property and does not want it to get wet unnecessarily, especially during trip testing when they test the deluge system. 

The sprinkler system is an open-head deluge system, except for these few regular pendent sprinklers.

Are these pendent sprinklers acceptable to be installed on a deluge system?

I was under the impression that only open-head sprinklers could be used on a deluge system.

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I inherited 3 sites each with multiple sprinkler systems (2 or 3 depending) on "plant air". The problem is the compressors assigned to deliver said plant air are only robust enough to air up a single component system within 30 minutes.

During the fall, we experience drastic temperature drops at dusk that result in pressure drops across all systems simultaneously, that effectually over-task the lone compressor at each site. The compressors run until the overtemperature cut-off pops, and they've been leaking oil from the head gasket due to overheating.

I'm perfectly willing to buy a $5k compressor, but they're typically 3 phase. I'm also willing to buy 2 or 3 small compressors/riser and cap the plant air line, but in either case the greater expense is running AC power to the risers, or upgrading the current plant air circuit voltage.

A permutation of the above 2 options would be to run 2 -$700 compressors in parallel at the current plant air site to split the CFM output requirement. I would have to run a 2nd dedicated circuit to the existing compressor locations, but it's in relatively close proximity to the panel.

To do so I am assuming I would need to wire the on/off pressure switches to an air maintenance device. I need them to come on and cut off at the same time, or else one will run to failure, the pressure bleed down, then the redundant compressor will run to failure. I'm worried that modifying the new compressors will void their warranties (which I acknowledge I may have to live with).

Does anyone have a diagram and parts list for how to use 2 compressors in tandem? Any recommendations for most pragmatic fix?

​Thanks in advance.

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Who has dealt with the question of egress from the vault of a linear accelerator (used to treat patients)?

The vault can only be opened from the inside by a button which can be disabled from the outside! The only manual opener is a crank on the outside!

I realize the patient could be incapacitated but what about maintenance and cleaning crews? Any recommendations, especially from those with experience, would be appreciated.

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I'm working on a project with an overhang that has patient rooms above. The ceiling of the overhang serves as a "canopy" for ambulances, which will back in under the overhang to protect patients from the elements when unloading the ambulances.

The design and completed construction do not include any fire suppression including sprinklers.

Are sprinklers required for this canopy?

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We are sprinkler protecting a building with all I-Beams (W-type) and they are considered Obstructed Construction. The maximum beam depth is 20-inches. All my deflectors are 20" down from the deck. 

The owner now wants to put sound panels in each of the beam pockets which will take up about 85% of the space and will hang level to the finished floor but at least 9-inches up to 19-inches down from the deck because the steel slopes.

Would additional sprinklers be needed above these sound panels?

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When/why would an eccentric reducer ever be installed on a fire pump's suction side with the flat side on bottom?

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Is it permissible to consider the refill supply for a water storage tank when sizing the tank?

The supply would come in above 20 psi. Thanks in advance.

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Where exactly is a remote area for a fire sprinkler hydraulic calculation drawn with respect to interior and exterior walls?

Is the remote area boundary along the inside, centerline, or outside edge of a wall?

Also, are small wall cavities or unsprinklered shafts right in the middle of a remote area included in that remote area square-footage?

I recognize that as much as I can fine-tooth a layout this really doesn't matter much in the overall scheme - and I typically would add a sprinkler or two to a calculation if the exact location of the remote area boundary would make or break an area threshold - but I've been curious about this as I'd like to be consistent with code and what should be done.

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We have a project where the AHJ is telling us they want the waterflow alarm to be silenceable. Our understanding under NFPA 13-2019 7.7 and 28.2.3.1 is that there must be an audible alarm within 90 seconds (per NFPA 72) and must continue until the flow stops, not when the fire alarm system silences the flow.

Are we correct in that waterflow is a non-silenceable event, by code?

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A couple recently submitted questions relate to the same topic: 

(1) Extra hazard, grid pipe layout of approximately 1,800 sprinklers. What is the criteria that drives the specific number of sprinklers that will be operating together?

(2) What's the best way to determine the design area and number of sprinklers within a calculation for a parking garage?

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I have a project with cloud ceilings that are 80 sqft clouds with a 2-foot separation around each cloud. I have no intention of omitting the sprinklers above the clouds. I plan to locate sprinklers in each cloud, considering them obstructions greater than four feet.

Do I need to space the sprinklers in the clouds to just cover beneath the cloud?

Just want to confirm that spacing doesn't need to be across the cloud ceiling when sprinklers are in different clouds. Thanks in advance.

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I have a double fire wall (two masonry walls next to each other with small air gap in-between). I need to have a door in each wall.

The doors would have to swing opposite directions, I think, which means a double Firewall could not be used in an egress condition where doors both have to open in the direction of travel to the exit.

It sounds like I need a tied or cantilevered Firewall instead of a double Firewall. Is this correct, or are there any other approaches to a door within a double Firewall?

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We have a project where transformers are located on the periphery within a building's ground floor. There are 14 transformers within a single room. The life safety consultant has recommended for us to provide deluge system protection.

Is it required to provide a deluge valve for each transformer, or combine three or four transformers per valve?

Also, how should sprinkler flow demand - is it calculated by each nozzle, or should we consider the entire transformer area for protection? Under NFPA 15 we have assumed 0.25 gpm/sqft (or 10.1 lmin/sqm).

​Thanks in advance.

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Does anyone know of a dry-chemical or equivalent fire suppression system that can be used in cold environments (as low as -20 degrees Fahrenheit)?

The space to be protected is a testing chamber approximately 8 feet by 11 feet (made of combustible materials). Automatic fire extinguishers are not an option as they don't have any UL rating. Thanks in advance.

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I have a project where there are multiple cloud ceilings with minimal gaps in-between. The clouds are 3'-6" wide, and the gaps between them are approximately 3-inches. Below is an image of the reflected ceiling plan.

Are sprinklers required below these cloud ceilings? Thanks in advance.

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I have a project where the fire pump room is located on a third floor level.

Are there any specific requirements regarding the location of a fire pump? Is this location acceptable?

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