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I'm designing a system with sprinklers at the ceiling of a large open space. There is a vestibule within this space that has a lower ceiling that requires 3 sprinklers. The client does not want pipe drops or hangers above the vestibule to be visible from the rest of the open space.
The proposed solution is to run a branchline down the wall and horizontal tight to the ceiling. Is there a good way to support this that meets the requirements of NFPA 13 chapter 9? The vestibule has CMU walls and metal stud ceiling. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe
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Determine the visibility (in meters) for a light reflecting exit sign with smoke that is produced by pyrolysis of plastic. Assume the smoke has a mass concentration of 0.09 grams per cubic meter.
a. 4.4 m b. 7.6 m c. 11.7 m d. 20.2 m A building owner has bought a large old warehouse and in about 6-8 months will convert it into educational spaces. They've asked if over the winter they could drain down the large wet sprinkler system as they aren't planning on heating the space or occupying the building during that time.
I recommended against it since they'd be without protection during that entire time and a fire could result in a total loss of the building. I also suggested they speak with their property insurer, couldn't store anything in the building, and would need to talk with the fire department as it would be a system impairment. Aside from that, what other barriers would they come across? What would you have recommended? Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe The activation time (in seconds) of a standard response (RTI of 85 m^1/2s^1/2), Ordinary Temperature (65 deg C) heat detector within a room that has an initial temperature of 22 deg C and exposed to a ceiling plume at 78 deg C traveling at 2.3 m/s is most nearly? a. 10 s b. 36 s c. 54 s d. 82 s Solution | Posted 10/18/19
This project is a residential occupancy (dormitory) with a sprinkler system designed under NFPA 13. The contractor is using residential-style sprinklers within each unit, but standard-spray sprinklers in the corridor.
The corridor has these standard spray sprinklers just off the main which runs down the corridor. The contractor has provided calculations for the four most demanding adjacent residential style sprinklers, which is fine. He's also provided a calculation for the corridor using five sprinklers. NFPA 13-2016 11.2.3.4.2 states: 11.2.3.4.2 Where an area is to be protected by a single line of sprinklers, the design area shall include all sprinklers on the line up to a maximum of seven. Since the corridor's sprinklers are not residential, how many sprinklers should be calculated in the corridor? Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe Which of the following occupancies have no difference in maximum permitted travel distance for sprinklered versus unsprinklered buildings? a. Existing Day Care b. Residential Lodging c. Existing Mercantile d. New Business Solution | Posted 10/17/19
This is giving me heartburn. A clothing manufacturing company wants to store group IV commodities.
16.1.3 Movable Racks. Rack storage in movable racks shall be protected in the same manner as multiple-row racks. 16.2.1.2 Protection Criteria for Rack Storage of Class I Through Class IV Commodities Stored Up to 12 ft in Height. 16.2.1.2.1 The protection criteria for storage up to and including 12 ft shall be the same as miscellaneous storage from Chapter 13. The definition of Compact Storage Module does not specify passive protection to qualify as such. My question is: “Is it correct to treat this rack configuration as moveable racks?” Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe Which of the following types of pipe would require the most hangers for the same length of 1-1/2" pipe? a. CPVC b. Copper Tube c. Steel other than Threaded Lightwall d. Threaded Lightwall Steel Solution | Posted 10/16/19
Have a flow test in a semi-rural area that has static pressures of over 130 psi but a residual pressure of 60 psi at just 500 gpm.
A flow test from nearly a decade ago shows worse results - with a static of around 120 and a residual of 20 psi at just 600 gpm. My initial concern with the older flow test was a partially-closed valve or obstruction in the line. With the newer test the residual pressure seems more reasonable, but other than something being wrong with the system is there a reason that would justify a residual pressure less than half the static at only 500 gpm of flow? Perhaps a system fed with small pumps and no tower? What are your thoughts? Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe If Element A is a 45-minute interior door, B is a corridor, C is a 2-hour rated stair, and D is a non-rated exterior door, which element identified would be considered an exit?  a. 45-minute Interior Door A b. Corridor B c. 2-hour Rated Stair d. Non-Rated Exterior Door Solution | Posted 10/15/19
 The Leaderboard lists the top total scores for the most recent three weekly exams for PE Prep Series participants. See the entire scoreboard here.  Want to join in? It's not too late - the PE Prep Series is the ultimate PE Prep tool. It's a series of 1-hour, 10-question simulated PE Exams offered weekly with solutions immediately following each exam. Learn more here. Every week of the series is retroactive so you can still test yourself with past week exams  NFPA 72 states that audibility from a fire alarm system is required to be provided throughout a building. Most jurisdictions are less concerned with attaining audibility in small, non-normally-occupied rooms such as janitor closets, small electrical rooms, or small mechanical rooms. However, several military reviews have pointed to exactly these rooms and asked how audibility is going to be achieved.
I typically provide speakers just outside of these groups of rooms such that there should be an achieved audible level, but how could I prove that during the design phase? Is there any calculation for audible loss through a door or software that could model this loss? I feel like there's a good handful of variables that play into whether audibility is achieved in these small rooms that may be difficult to predict. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe An oil field site has a potential for detonation of an equivalent of 180 lb of TNT at its main plant. Determine most nearly the minimum distance where an adjacent oil storage tank would rupture at this energy. a. 50 ft. b. 80 ft. c. 100 ft. d. 150 ft. Solution | Posted 10/14/19
Is there a complete list of points I need to monitor with fire alarm for a diesel driven fire pump?
I can't seem to find a comprehensive/definitive list in NFPA 20 or 72, but I would imagine at least one or more of the following would need to be monitored by code: fire pump running, primary sensor failure, low fuel level, main disconnect in "off" position, main disconnect in "manual" position, low pump room temperature, flowmeter left on, loss of AC power supply, loss of battery (load side of DC overcurrent), over-speed, and engine trouble (low oil, over temp, other?). Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe Which of the following would be considered a typical fire load for a bedroom? a. 0.4 - 0.8 lb/sqft b. 3.2 - 5.5 lb/sqft c. 11 - 14 lb/sqft d. 43 - 48 lb/sqft Solution | Posted 10/11/19
NFPA 13 (2016 Edition) Section 9.2.1.4.1 states:
9.2.1.4.1 Branch line hangers attached to metal deck shall be permitted only for the support of pipe 1 inch of smaller in size, by drilling or punching the vertical portion of the metal deck and using through bolts. The Sammy X-Press has listed hangers that call out attachment directly to metal deck for pipe up through 4" in some cases. From a code perspective, does the section above not apply, or would this be a code approved alternative? Just looking for the code logic that would allow use of listed special materials where the section above wouldn't trump this method. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe If the relationship below describes the growth phases of fire, what point does the arrow indicate? a. ignition b. ceiling jet creation c. flashover d. growth  Solution | Posted 10/10/19
I came across a specification requirement I've never seen before.
The specifications called for "sprinkler systems that require a fire pump to meet sprinkler requirements, all sprinkler pipe sizes shall be based on the Pipe Schedule method. This is to provide maximum sprinkler operation when the fire pump is not available, and minimizes the size of the fire pump. This also provides the possibility that with future water infrastructure improvements, the fire pump would no longer be required." A few questions about this - first, if the Pipe Schedule method could be used, wouldn't a fire pump not be necessary in the first place? Second, has anyone ran into something like this before and designed their system that way? For large facilities the only cost savings that comes back with having a fire pump is better pipe sizing. If that goes away, I could see the fire pump being a major cost burden above and beyond what it already is to the owner. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe A fire pump's speed is altered from 1760 to 1800 rpm. What is the new head if the original was 120 ft? a. 115 ft. b. 123 ft. c. 126 ft. d. 128 ft. Solution | Posted 10/09/19
I have been asked to design a sprinkler system for a 4 story building as per NFPA 13R. The building has existing standpipes consisting of three 2 1/2” risers. I am hoping to use the existing standpipe risers to also feed the sprinkler system.
In this scenario would it make sense to include a hose allowance even though NFPA 13R does not require it? Also, since NFPA 13R doesn’t require zoning by floor, would it be plausible to have one single “Standpipe & Sprinkler Water Flow Alarm” at the water entry? I appreciate and respect your input. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe A manufacturing facility's campus water supply is fed from a 125-foot tall open atmosphere water tank. A site fire pump is located 5 feet above grade and is flowing at its rated capacity of 35 psi at 1000 gpm with 18 psi loss in the total pipe network, what will the pressure be at the pump discharge if the discharge pipe is 4 inches in diameter?  a. 48 psi b. 56 psi c. 64 psi d. 71 psi Solution | Posted 10/08/19
Thank you to all forum contributors for September. We're continually seeing an uptick in interest and expertise, and I appreciate your willingness to encourage growth in our industry with your contributions! Here's the top commenters for September:
 The Leaderboard lists the top total scores for the most recent three weekly exams for PE Prep Series participants. See the entire scoreboard here.  Want to join in? It's not too late - the PE Prep Series is the ultimate PE Prep tool. It's a series of 1-hour, 10-question simulated PE Exams offered weekly with solutions immediately following each exam. Learn more here. Every week of the series is retroactive so you can still test yourself with past week exams
Being told I need two fire dampers to serve a single fire wall. The fire wall is made of a "double wall", essentially two masonry walls next to each other with a very small (less than 2-inch) air gap in-between. The engineer on the project is stating that this "double wall" requires a fire damper in each.
I've never come across this as a requirement before. Do I need two fire dampers? Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe A high-rise building is to use a pressurized tank (half air-half water) to supply automatic sprinkler systems. If hydraulic calculations determine that 55 psi is required to supply the sprinkler system, what tank pressure is required? a. 55 psi b. 95 psi c. 125 psi d. 140 psi Solution | Posted 10/07/19
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