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A new building is to have a wet pipe fire sprinkler system connected to an existing city main. Which of the following tests is not required by NFPA 13 for the fire sprinkler system or underground service? a. flushing test b. hydrostatic test c. main drain test d. water delivery test Solution | Posted 10/06/20
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Last week was week eighteen of our 2020 PE Prep Series - it's 20-weeks worth of mini Fire Protection PE Exams. Each week we'll post the leaderboard here with the results of that week's exams. To see full leadership board and more details, visit the PE Prep Series page here  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.
In an existing building with no fire pump test header, is it permissible to use Standpipe 2-1/2" fire hose cabinet valves to conduct a flow test for smaller pumps?
I believe NFPA 20 (2019) 4.22.3.1.3 (2) indicates that this approach is acceptable, but I would like to confirm. Submitted anonymously and posted for discussion. Discuss This | Submit Your Question | Subscribe In which of the following scenarios is neither explosion protection nor suppression system required? a. Flammable paint warehouse mixing rooms where open transfer of paint occurs b. Dust ventilator equipment where the dust density can be above its lower flammability limit c. Mechanical room where service equipment is subject to explosion d. All of the above require either explosion protection or suppression systems Solution | Posted 10/05/20
At our site I'm dealing with personnel wanting to park small vehicles (Gem carts and forklifts) inside the building.
I know this is clearly not allowed in an egress corridor (where it was) but I'm having trouble finding parts of the code addressing storage in mechanical rooms or similar space. I know NFPA 101 has rules for high hazard contents but not sure if I can make that argument for the vehicles. Any thoughts or suggestions? Thanks in advance. Submitted anonymously and posted for discussion. Discuss This | Submit Your Question | Subscribe 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. This past month we've had great submitted questions and thorough responses where everyone benefits. Thank you! Here are the top contributors from September 2020:
White Oak wood having a density of 450, moisture-content of 25% is exposed to a standard fire (ASTM E119) test for 2 hours. What is the expected char depth most nearly? a. 1 mm b. 64 mm c. 78 mm d. 224 mm Solution | Posted 10/02/20
Has anyone seen the International Fire Code Chapters 53 and 58 applied to natural gas installations in addition to the Fuel Gas Code?
IFC Chapter 53 is Compressed Gasses and Chapter 58 is Flammable Gasses. It's technically a gas at standard temperature and pressure with a boiling point below 68 deg F at 14.7 psi and flammable range of 5% to 17% by volume in air. Natural gas appears to be subject to these requirements, but I've never seen it this way in practice. Submitted anonymously and posted for discussion. Discuss This | Submit Your Question | Subscribe An elementary school must perform a fire drill at least: a. Once per month b. Once every other month c. Once per semester (twice each year) d. Once per year Solution | Posted 10/01/20
Recently had a job with a wet-pipe fire sprinkler system (smaller project) that has a 6-inch double check backflow. The area static and residual pressures are pretty consistent (had a flow test of ~40 psi static and ~38 psi residual at 1,300 gpm).
We ran a forward-flow test through the backflow preventer, needing a minimum flow of about 800 gpm, which includes the hose allowances for the project (no standpipes or interior hose connections). The most flow we could get was about 450 gpm, even with three 2-1/2" hose outlets completely wide open. The static pressure following the test at the riser was about 40 psi. We used three 100 ft, 2-1/2" hoses with a 1-3/4" smooth nozzle and diffusers at the end of each hose, measuring about 3 psi pitot on each and full flow (which equates to roughly 450 gpm). Do you have any tips or advice in why we were not able to get enough flow through the backflow, or where to start to troubleshoot? Thanks in advance! Submitted anonymously and posted for discussion. Discuss This | Submit Your Question | Subscribe The pressure gradient that causes a liquid to move through the intake line to the pump impeller is: a. total static head b. net positive suction head c. net discharge head d. rated head Solution | Posted 09/30/20
Is it possible to make a 60-degree angle to a main pipe using grooved pipe and fittings?
If I'm correct there is only 90-degree, 45-degree, and 11.5 degree angles normally available. If a 60-degree angle is impossible, is there a way to use welded parts to make this angle happen? What's my best option here? Submitted anonymously and posted for discussion. Discuss This | Submit Your Question | Subscribe Last week was week sixteen of our 2020 PE Prep Series - it's 20-weeks worth of mini Fire Protection PE Exams. Week 17, #1 had a question that required calculation of an effective heat transfer coefficient. Technically this doesn't show up in any reference material, so points were rewarded to each examinee on this question. It's been revised for future versions. Each week we'll post the leaderboard here with the results of that week's exams. To see full leadership board and more details, visit the PE Prep Series page here  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.
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 Solution | Posted 09/29/20
How do I properly perform hydraulic calculations for a sprinkler system with two water sources?
The system we have is supplied by two independent street mains. Each service has a slightly different static and residual pressure. The calculations need to show both supplies. Thanks in advance. Submitted anonymously and posted 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 09/28/20
We have a closed ammonia refrigeration system for a large cooler/freezer. The refrigeration equipment is located in a separate mechanical room. Total amount of ammonia is less than 10,000 lbs.
My question is explosion control per Section 911 of the International Fire Code required for the refrigeration mechanical room? I am reading different interpretations on whether ammonia is considered a flammable gas, most say it is technically not a flammable gas but can burn and/or explode. I'm interested in hearing everyone's take. Thanks. Submitted anonymously and posted for discussion. Discuss This | Submit Your Question | Subscribe A stair is 59 inches wide, with a handrail on one side with a centerline of 1.5 inches from the edge of the stair. The other side of the stair is a wall. For the purposes of calculating a specic ow, what is the effective width of the stair? a. 47 in. b. 48 in. c. 53 in. d. 59 in. Solution | Posted 09/25/20
I'm an AHJ and I know many plan reviewers and inspectors in my area are new to the trade.
Does anyone have recommendation(s) for good plan review checklists or tools for plan review that would be helpful to rookie and intermediate-level plan reviewers? Thanks in advance. Submitted anonymously and posted for discussion. Discuss This | Submit Your Question | Subscribe A continuous membrane with a fire protection rating constructed to limit the spread of fire is which of the following? a. smoke partition b. fire compartment c. fire barrier d. proscenium wall Solution | Posted 09/24/20
What is the average life expectancy of a wet and dry fire sprinkler system?
Submitted anonymously and posted for discussion. Discuss This | Submit Your Question | Subscribe Fire sprinkler system design has been based upon all of the following except: a. Empirical flow and pressure loss calculations b. Application of experienced judgement and reasoning c. Mathematical suppression modeling d. Evolutionary changes based on fire loss Solution | Posted 09/23/20
NFPA 22, 2018 Edition regarding filling requirement and duration -
Section 4.2.1.4. states "The water supply shall be capable of filling the minimum required fire protection volume within the tank in a maximum of 8 hours" and at the same time Section 14.4.3 states "The tank shall be kept filled, and the water level shall never be more than 4 in. (102 mm) below the designated fire service level." If I understand correctly, as soon as the water goes below 4-inches from the normal filled level in the tank (HHL), the makeup water supply should be starting to replenish and the pipe sizes should be provided in such a way that the tank can be filled within 8-hours. In a fire, as the water is going down, the tank will always start full. What is the case where the tank would be emptied out (except maintenance) and need to be refilled within 8-hours? What if we store water in two tanks to allow maintenance - would we not need to meet this 8-hour requirement? I'm unsure of how these two requirements work together. Appreciate any feedback. Submitted anonymously and posted for discussion. Discuss This | Submit Your Question | Subscribe Last week was week sixteen of our 2020 PE Prep Series - it's 20-weeks worth of mini Fire Protection PE Exams. Each week we'll post the leaderboard here with the results of that week's exams. To see full leadership board and more details, visit the PE Prep Series page here  he 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.
If, during a fire, a total occupant load of 185 people are exiting through a building's main entry (a 7-foot double door with an effective width of 6.5 ft) and the density near the main exit door results in about 0.25 persons/sqft, the time (in minutes) it would take for all of these occupants to exit the main doors is most nearly: a. 1.3 min b. 1.4 min c. 2.0 min d. 5.7 min Solution | Posted 09/22/20
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