Is there a reason why OS&Y would be better on backflow preventers for fire suppression systems over butterfly valves?
One application where we often must use the OS&Y is when the backflow serves a fire pump and we don't want to distort the flow and cause cavitation at the pump - but otherwise the butterfly valves are a major space saver. Just curious if others feel differently or if I'm missing a major benefit to the OS&Y type. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe
6 Comments
A 4-inch schedule 40 main is routed parallel in-between two beams and requires a trapeze hanger. The main is 2 ft. from one beam and 8.5 ft from the other for a total span of 10.5 ft. What is the smallest schedule 10 pipe capable of supporting this main as a trapeze hanger? a. 2 inch b. 2-1/2 inch c. 3 inch d. 3-1/2 inch Solution | Posted 06/17/19
The 2015 Edition of the International Fire Code added some clarity for water supply for buildings with automatic sprinkler systems.
The Annex B material (not enforceable unless adopted) states: B105.3 Water supply for buildings equipped with an automatic sprinkler system. For buildings equipped with an approved automatic sprinkler system, the water supply shall be capable of providing the greater of: 1. The automatic sprinkler system demand, including hose stream allowance. 2. The required fire-flow. In the past I've heard several people say that only inside hose allowances are included when determining the total volume required (which sizes the water storage tank). Would you interpret this section of IFC to include both the inside and outside hose allowance? Posted anonymously 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 06/14/19
Where concrete anchors are used for seismic bracing, they must be "prequalified". Is this just an additional listing that is required to meet ACI 355.2?
Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe In general, when designing fire sprinkler systems with a fire pump, is your philosophy to only provide the minimum fire pump size that is needed to support your system, or do you often increase the fire pump size to decrease pipe sizes on the system?
How much are you typically willing to increase a fire pump size in order to benefit the pipe sizes throughout your project? When I first learned about how to size a fire pump, I was told that if your system gets over 100 psi then you might as well size the pump to get as close to 170-175 psi on the system as possible - the reason being that the cost to upsize a fire pump is less than the savings associated with smaller mains and branch pipe. I'm not sure that there's a hard-and-fast rule of thumb, but I'm just interested if other people use the same strategy or if it's entirely dependent on the type of job and size of the job. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe What is the ideal approach for fire sprinkler pipe to enter a building?
I find many engineer details show either an in-building riser (by Ames) or a ductile iron pipe with restrained pipe and fittings come under the building foundation and up into the building. While this approach is acceptable, if we have the ability to coordinate with the structural foundation during design, would it not be better to drop the footing so that the fire sprinkler pipe can be sleeved through the vertical portion of the foundation wall? I would think that running through the foundation wall would put far less pressure onto the pipe and joints itself. I understand when most installation/design work is completed is usually well after structural design, but when we do design upfront wouldn't this be the best-case scenario? Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe On recent inspections I've seen many installations where an automatic ball drip is not provided anywhere on the pipe connection between the fire department connection and the check valve that serves the fire department connection. Is there an exception I'm missing or isn't that automatic ball drip always required?
Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe Have a unique scenario I'd be interested in other's take on. Eight-story building with automatic standpipes and a fully-sprinklered building. There's multiple scenarios where the building is close enough to an adjacent building that the exterior wall needed to be rated. In order to keep the fire resistance rating Tyco window sprinklers were installed in conjunction with glass to provide up to a 2-hour fire resistance rating.
The issue is that the sprinkler system experiences a working pressure of up to 220-230 psi, while the window sprinklers are only available as rated up to 175 psi. We've proposed adding pressure reducing valve to the seven floors affected by this situation, but that introduces its own issues aside from cost. We've also suggested replacing the glass with a rated glass. Are there other alternatives we haven't explored here? Would be interested in others' opinions. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe A 500 sqft rated liquid storage room is to be created within a fully-sprinklered 200,000 sqft warehouse. How many 55 gallon drums of Class IIIB liquid (flashpoint above 200 deg F) can be stored within this room? a. 18 containers b. 36 containers c. 87 containers d. 90 containers Solution | Posted 06/06/19
Without the context of a specific project or problem, when would you recommend creating a separate, detached fire pump house versus a fire pump room inside a building?
Is is purely a risk perspective? Do you recommend fire pump houses only when a pump is feeding multiple buildings, or a campus? I've only had a few projects that used a fire pump house, and it has generally been in retrofit situations or when the pump is next to a water storage tank. In either case the pump house overall cost more than it would have should the fire pump room been within the building (even despite the simple construction of the pump house). Just curious on getting another perspective. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe As best I can tell there's no listed bracing method for longitudinal seismic bracing for CPVC. Traditionally we've addressed this by placing a tee with a short pipe stub perpendicular to a main and braced that perpendicular pipe with a "lateral" brace, which acts longitudinally on the main. The downside to this is that it's not concentric to the main, but it's pretty close.
Is there a better way to brace CPVC pipe longitudinally? Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe I've looked for it but I'm having a tough time coming up with the code section. Where does the requirement for a bell on the face of the building come from?
Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe From my uneducated perspective both concrete anchors and wood attachments that most people use in the field are not the prescriptive methods outlined in NFPA 13, but instead listed products that are easier to install.
In the interest of learning more about what's actually preferred by contractors, are there any good articles or book content anywhere that could help bring me up to speed on these various hanging attachments? Any help is appreciated. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe A project we're working on has an existing basement area that is broken up into many small existing rooms. Each room has varying ceiling heights and different grid directions.
The remodel that is going to be done will change all of these small spaces into three areas with a consistent new ceiling height that is about the average height of the existing ceilings. If you are the engineer preparing bid documents in a scenario like this, would you call out for full pipe replacement, or only to modify the existing branch lines? I would be interested in how others approach this issue prior to bid. On one hand, modifying the existing system has the potential to save a significant amount of pipe, but could require some large stretches be raised to accommodate new ceilings and would require a good handful of labor to relocate sprinklers. On the other hand, while an all-new pipe arrangement may cost more in material, it would be better able to coordinate with new HVAC ductwork and ceilings in the space and could possibly reduce the labor time with a pre-fabricated install. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe
Hope everyone is having a great week. We're wrapping up this week's Daily Forum with a poll for use of software for hydraulic calculations. Don't see the poll below? Vote here.
If you would like to see your question (or poll) posted, please send it in or email us at [email protected]. Thank you! ​ I've taken technical writing courses and have experience working with MasterSpec, US Military specifications, vendor specifications, and various ownership standard specifications.
I'm giving an internal training to our younger staff and I'm particularly interested in opinions from contractors and vendors who regularly read a variety of specifications for bidding. What advice would you give for those who write specifications? I'd be interested in helping train our staff as well as improve myself. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe For years on my code calls I have asked the Authority Having Jurisdiction what the maximum distance the nearest hydrant is allowed to be away from a building's fire department connection. I get answers that range from 50 feet to 400 feet or even more.
I was looking into the code basis behind this question, and the only applicable section that I found is the International Fire Code, Section 507.5.1.1 that addresses hydrant locations for standpipe systems: "Buildings equipped with a standpipe system installed in accordance with Section 905 shall have a fire hydrant within 100 feet (30 480 mm) of the fire department connections. Exception: the distance shall be permitted to exceed 100 feet (30 480 mm) where approved by the fire code official." Is there any relevant requirement for hydrants near fire department connections for sprinkler-only systems? Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe Pressure Reducing Valve are commonly used to prevent excess pressure upon systems when supplies exceed the NFPA limit of 175 psi.
There has been much discussion regarding the 'application' of these valves when hydraulic calculations are being provided to the discharge of the PRV and determining the pressure margin available. Currently, we have been instructed to calculate the system back to the PRV, use the PRV's friction loss calculator to determine friction loss through the valve and subtract that from the outlet setting to establish outlet pressure. This is then used as the available pressure at the outlet; minus the demand and you're left with the margin. I'm not sure that I agree that the valves 'friction' loss need to be considered unless you are at a point where the PRV can no longer provide the set pressure (when the supply is unable to provide sufficient inlet pressure to overcome the internal friction loss). Are there any 'papers' written for direction or other sources anyone might recommend? Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe Amazon is selling fire sprinklers, escutcheons, and sprinkler guards. Some are UL Listed. But many are not listed for use together.
Because of the strict code requirements for installation and testing, is this appropriate marketing? Who is liable for improper installation and system component failure? Who approves this? Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe Have a project where the client is wanting fully-concealed sprinklers, but the project is insured under FM Global. FM does not approve any fully-concealed sprinklers as quick response.
However, under NFPA 13, light hazard spaces are required to have quick response sprinklers. How do you normally address this conflict? Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe We're located in a seismic area where PT decks are to be considered cracked concrete for the purpose of hanging and bracing. We see a lot of the Dewalt Mini Undercuts and now the newer Hilti HDP-TZ inserts being used to hang up to 4" pipe from the concrete decks. The data sheets show them with pullouts of under 240lbs.
How can these be used to hang ANY sprinkler pipe if the minimum required capacity of the hanger assembly is the weight of the water filled pipe plus 250lbs? Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe Basic question but I don't know the history - why do we limit pipe to 21-foot lengths? Manufacturing limitation? Transportation? Just curious on the history there.
Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe NFPA 14 requires standpipes to be full flow tested for the acceptance testing.
Automatic standpipes are fairly straightforward to test, but how have you seen this applied for manual standpipes in mid-rise buildings? Is this a worthwhile test that will uncover design/installation flaws? Also, is there any compromised method to meet this requirement? Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe In a residential dwelling unit of a high rise building, would a drum light fixture (7"h x 14"d) qualify as an obstruction?
It’s a concealed head in a residential unit of a senior living building. The contractor – of course – doe not have exact dimensions because it wasn’t reflected on the plans and was added later as a lighting option and only caught by my inspectors during Rough-In. As it is installed, the head is a few inches from the fixture in some units and “a few feet” in others. They want to add a head on the other side of the light, approximately 3 feet -4 feet away citing NFPA 13 8.10.6.2.1.4. I feel that the light, while an obstruction, doesn’t count as continuous nor does it meet the requirements of a baffle, so if they want to add another head it’d have to be at least 6 feet away to prevent cold solder. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe |
ALL-ACCESSSUBSCRIBESubscribe and learn something new each day:
COMMUNITYTop June '24 Contributors
YOUR POSTPE EXAMGet 100 Days of Free Sample Questions right to you!
FILTERS
All
ARCHIVES
July 2024
PE PREP SERIES |