A FORUM FOR FIRE PROTECTION QUESTIONS & PE EXAM PROBLEMS | SUBSCRIBE NOW
|
In preparation for the PE Exam, the fire dynamics content is my weakest subject. I am looking to take some classes on fire dynamics, do you have any suggestions?
Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe
3 Comments
A portion of a home-improvement store has K11.2 ceiling-only sprinkler protection above double row racks. The owner is looking to store bagged charcoal (without any impregnated ignition fluid or plastic wrap) atop reinforced plastic pallets in this area. What would the commodity classification be for this arrangement if no plastics are intermixed? a. Class II b. Class III c. Class IV d. Group A Plastic Solution | Posted 08/01/19
Lately I have seen a couple specifications require branch lines to have threaded connections and they specifically do not allow grooved, even when Schedule 40 pipe is used and even when most of the armover connections are welded pipe outlets.
These could just be old/outdated specs, but is there a reason/theory that suggests threaded connections are better than grooved? They can be cheaper but also can increase labor costs on large jobs. Just curious if there's a perspective I'm not considering here, thanks in advance. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe  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
Which of the following would not require a fire alarm system? a. A new second-floor tenant insurance sales office of 60 people b. An existing four-story fraternity house of 70 people c. A single-story 80,000 sqft high-hazard warehouse of 90 people d. A new single-story 35,000 sqft Class A department store Solution | Posted 07/31/19
Which of the following plastics has the lowest decomposition temperature? a. PBT (polybutylene terephthalate) b. PET (polyethylene terephthalate) c. PMMA (polymethyl methacrylate) d. PTFE (polytetrafluoro ethylene) Solution | Posted 07/29/19
Calculating the required size of a thrust block using the information in NFPA 13.
What angle (degree) would I use for a Tee fitting or dead end? Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe Is fire flow calculated on only one building at a time, or must all buildings in an area be considered when determining the required amount of fire flow?
We have a school property with one school that's comprised of many 'buildings' separated by fire walls. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe The static discharge head equals the sum of all of the following except: a. Total static head b. Discharge system losses c. Suction system losses d. Net suction head Solution | Posted 07/26/19
I was reviewing a sprinkler plan using flexible house from an arm over. The head had a k factor of 5.6 and the flexible hose had a k-factor of 4.86 with the pressure and flow at the head. This seems like a mistake. Wouldn't you want a flexible hose with a k-factor of 5.6 or larger?
Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe A starch processing facility handles and processes starch dust. The plant's process has equipment which, under mechanical failure, could produce combustible dust in some areas of the facility. What type of truck would be permitted in these areas of the facility? a. Electrical Type EE b. Electrical Type ES c. Diesel Type DY d. Gasoline Type GS Solution | Posted 07/29/19
The International Building Code Section 707.5.1 (2015 Edition) requires structure to have at least the level of fire resistance as the element it is supporting:
707.5.1 Supporting construction. The supporting construction for a fire barrier shall be protected to afford the required fire-resistance rating of the fire barrier supported. Hollow vertical spaces within a fire barrier shall be fireblocked in accordance with Section 718.2 at every floor level. Exceptions: 1. The maximum required fire-resistance rating for assemblies supporting fire barriers separating tank storage as provided for in Section 415.9.1.2 shall be 2 hours, but not less than required by Table 601 for the building construction type. 2. Supporting construction for 1-hour fire barriers required by Table 509 in buildings of Type IIB, IIIB and VB construction is not required to be fire-resistance rated unless required by other sections of this code. The project is a three-story hotel and each unit is required to have a 1/2-hour fire resistance rating between units and between the unit and the corridor. Is the building structure required to have at least a 1/2-hour rating on account of these separations? I see two potential outs that would not require it - first being that the 1/2-hour fire resistance rating could be considered a "fire partition" and not a "fire barrier". Second out is exception #2 listed above although it speaks to a 1-hour rated fire barrier and not a 1/2-hour fire barrier. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe Balance the following combustion equation for hexane: C6H14 + (O2 + 3.76N2) = CO2 + H2O + N2 a. C6H14 + 6(O2 + 3.76N2) = 6CO2 + 7H2O + 6(3.76)N2 b. C6H14 + 19(O2 + 3.76N2) = 6CO2 + 7H2O + 6(3.76)N2 c. C6H14 + 19(O2 + 3.76N2) = 12CO2 + 14H2O + 19(3.76)N2 d. 2C6H14 + 19(O2 + 3.76N2) = 12CO2 + 14H2O + 19(3.76)N2 Solution | Posted 07/24/19
Have a current project that is stalled due to water supply conditions. A water flow test was not conducted early in the project.
Options have been presented to the other responsible parties for consideration, however a particular party has rebutted with “Where does it say you can not go below a certain water pressure?” The existing water supply would be taken down to 6 psi and the questioning party wants documentation on the standards of the lowest psi a water supply needs or should not drop below. Can anyone provide or give direction on finding information regarding water supply requirements or standards which address minimum water supply requirements? Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe  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
The amount of energy required to raise the temperature of 1 kg of fluid by 1 deg C is: a. Conduction Coefficient b. Enthalpy c. Entropy d. Specific Heat Solution | Posted 07/23/19
What is the fire protection standard for CT-Scan, PET/CT, tomotherapy, etc. rooms?
NFPA 13 notes only that occupancies shall have automatic fire sprinkler system or an approved alternative. I have seen double standards in installed systems in one hospital project I worked in wherein the hospital AHJ proposed wet sprinkler system on one occasion while clean agent fire suppression system was used on another. My concern is that an unconscious patient left inside the gantry by staff in panic can die if the clean agent fire suppression system discharges in the treatment room. Whereas, on another hand, millions worth CT, PET/CT, tomotherapy machines can be seriously damaged beyond repair if the wet sprinkler system works to put out fire inside the room. It sometimes seems like a choice between protecting patients which is the core business of healthcare facilities or protecting costly property from damage. Is there an absolute standard to put a period to my query? Thanks. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe Considering all potential components in a building, which of the following occupancies has the most restrictive requirements for material flame spread and smoke development? a. new day-care centers b. existing duplex home c. existing Class B department store d. new large warehouse Solution | Posted 07/22/19
Existing building with a vertical in-line fire pump that has not been tested in the last 5-6 years. The fire pump is fed from a water storage tank where the top of the tank is roughly 12-15 feet above the fire pump.
The fire pump is rated 55 psi at 500 gpm. There is about 60 feet of 4-inch main that connects the discharge side of the fire pump to the fire pump test header. This stretch of main also includes at least 6 elbows and a tee. The test header has two 2-1/2" connections. With a hose monster and 15-feet of hose connected to the pump test header, we are only able to flow about 400 gpm out of the test header. At this flow rate, the suction side fire pump gauge reads -20 psi and the discharge reads 25 psi. In short we are not getting the 100% flow (of 500 gpm) or the rated pressure (of 55 psi). I can see some flow being restricted due to the long run from the pump room to the building exterior, but are there other issues I'm not thinking about here that would cause this? Obstruction in the main perhaps? Any tips on actually getting the flow up to 100%? Thanks. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe Which of the following is not a preferred interface between fire alarm and smoke control systems due to the requirement for equipment to be listed as compatible? a. Equipment connected to Building Automation/Management System, which is connected to Fire Alarm by network connection b. Equipment connected to Building Automation/Management System, which is connected to Fire Alarm by electrical contact/relays c. Digital Control Equipment connected directly to Fire Alarm System via network connection d. Mechanical Equipment connected directly to Fire Alarm System via contacts/relays Solution | Posted 07/19/19
What is difference in the content in the NICET Level III and Level IV (water based layout)?
I am getting ready to test for the Level IV, I have read the test content outline from NICET, but just was wondering if it was more of the same (NICET Level III) or concentrated on certain topics. This is taking in consideration that the content outline from NICET has been read. The only designer I know with a NICET IV, tested with elements years ago. Thanks for any the time and help. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe Of the following substances, which would have the greatest total heat output for the same amount of mass? a. ethane b. methanol c. toulene d. vinyl acetate Solution | Posted 07/18/19
We have to provide sprinklers 4 feet on center to protect the opening between a commercial kitchen and a seating area.
The number of heads to be calculated is based on the 1.2 times the square root of 1500 per NFPA 13 2007 Edition. W have first calculated the water curtain demand assuming each sprinkler needs to flow 15 gpm. We get a required pressure and flow for the end node serving the water curtain. The calculated flow/pressure is then used in the full calc to balance the remaining system around. So in essence we are calculating the system in two parts. Is this the correct methodology? As best I can tell the water curtain demand must be in addition and must be balanced with the remote area. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe Extinguishment of fire by cooling the solid or liquid combustible is effective primarily because: a. the cooling prevents production of combustible vapors b. the cooling interrupts the chain reaction c. the cooling surface will condense moisture from the air, pre-wetting surfaces d. all of the above Solution | Posted 07/17/19
Are there guidelines/best practices for recommended pipe schedule in tall high-rise standpipe express risers?
The height could force the working pressure in the pipe to exceed 300 or more psi. Unless there is a better method I'm assuming the preferred joint is roll-grooved. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe |
Free SignupSubscribe and learn something new each day:
CommunityThank You to Our Top December '19 Contributors!
Your PostThe ToolkitSprinkler Designer or Engineer?
Get all of our tools, including the Sprinkler Database, Friction Loss Calculator, Fire Pump Analyzer and more: 
Filters
All
Archives
January 2020
Daily
Daily discussion questions are open-ended questions posed by members for the benefit of sharing expertise and learning from other perspectives. Join as a member here.
Exam Prep
2019 PE Prep Guide
(Available Now!) 
PE Prep Series
(Available Now!) Current Leaderboard
(Click to enlarge) 
PE Problems
Visit July-October for daily Fire Protection PE Exam sample questions.
Solutions are posted the day after posting. Comment with your solutions, questions or clarifications. Please note that questions posted are unofficial and in accordance with NCEES rules are intended to be similar to actual exam questions, not actual exam questions themselves. |
RSS Feed
