WEEKLY TAKEAWAYS AS A FIRE PROTECTION ENGINEER
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This week we're covering a basic riser manifold configuration for wet-pipe fire sprinkler systems. This is not for a shotgun-style single riser, nor for a wet riser using an alarm check valve (we'll explore both of those later). If you haven't checked it out, there are great ongoing discussions (some of which covered these topics) on the MeyerFire Daily page here.  Overview Wet-pipe systems form the backbone of traditional fire sprinkler system design, comprising the most popular and most economical system type available. Here's the major components that go into a wet-pipe fire sprinkler assembly: Check Valve
FDC Connection
Main Drain
Inspector's Test
Isolation Valve
Pressure Gauge
Waterflow Switch
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I receive feedback regularly from many users and observers - and I'm very grateful for both! Sprinkler Database Interest & Feedback One member recently reached out about the Sprinkler Database and said: "I appreciate all the work you’ve done on that site. The sprinkler database has helped tremendously when looking for specialty sprinklers, specifically available storage sprinkler is odd configurations!" It's a tool that is basic in premise but can save tons of time when you're looking to compare sprinklers, find a specific type of sprinkler, or see if a solution exists for your specific problem. Here's a quick overview Fire Pump Database With the interest and feedback from the Sprinkler Database, it was only a matter of time before I expanded this into other areas. You may already have seen the Backflow Database, but now we have a beta version of a Fire Pump Database. With the fire pump database you can now search for fire pumps of various configurations, drivers, sizes, and then instantly link to CAD and Revit models, performance curves, website links, product data, and dimensions. The current beta version includes AC, Armstrong, and Aurora Fire Pumps. All-inclusive Toolkit members can log in and use the database now.  Know a Contact for Patterson or Peerless? If you work for or know a great contact for Patterson Fire Pumps and Peerless Fire Pumps, please let me know their contact information. I'm looking to partner with both of these companies to also help connect users to their products. Toolkit Sale Through November 30th Interested in getting the Toolkit and access to all of our tools? Join between now and Friday the 30th for $30 off your first year's subscription. Just use coupon code CYBER18 when you checkout here before Friday November 30th. Lastly, if you're in the US, I hope you have a great Thanksgiving!
First, a big thank you to those who commented and emailed ideas and topics that contributed to the latest tool for this site - the Trapeze Calculator.
Quick Calc With only a few "knowns" (pipe diameter and schedule, and distances to nearest structure), you can now quickly calculate the section modulus that's required, visit options for the trapeze bar, and see these options schematically in a to-scale detail. Multiple Pipes Have multiple pipes on a trapeze? Calculate the section modulus required for each, add the two moduli together, and simply override the Section Modulus Required value below to see your options. Get CAD Details Want a CAD version of the detail? Sure thing - the downloadable All-Access Toolkit allows you to save and print these calculations as PDFs, which can then be imported directly into AutoCAD and use the ALIGN function to scale it to your drawing. ​Toolkit Users Already a Toolkit user? Install the latest version from your dashboard to get the updates to this tool. No new activation code is necessary. ​Don't see the tool below? Try it out here - This site is all about finding ways to help you be the office hero with quick and helpful fire protection tools. Get these weekly articles straight to your inbox by subscribing here.
First, a huge thank you to everyone who's expressed interest and purchased the Toolkit - I very much appreciate the fantastic response to the launch over the last three weeks!
It's a short post this week - I've been developing a Trapeze Hanger tool that sizes and schematically details trapeze hangers. This will likely be the first of three posts while developing this tool. Questions for you at this point in time: (1) What other possible standard trapeze materials do you use that could be helpful as part of this tool? (2) What would you like to see shown in the detail? (3) If the detail could be easily translated to AutoCAD from this calculator, could it be something helpful for your projects? If so, what would you want shown and identified? Click here to test and comment on the Trapeze Hanger tool, thanks in advance! ​ Know someone who might be interested in resources or articles like this? Forward to a friend. Don't get these articles sent weekly to your inbox? Subscribe here. One of the popular aspects of fire sprinkler installations that is overwhelmingly familiar to fitters in the field yet something I hardly understood back as a new graduate is pipe connections. Today I'm breaking out some of the popular methods of joining steel pipe in fire sprinkler systems. Steel Pipe While copper, CPVC and PEX are listed for use in fire sprinkler systems (PEX is only for NFPA 13D systems), black steel pipe remains the most popular pipe material for commercial fire sprinkler applications, at least within the United States. For steel pipe, the primary means of connecting the pipe include threaded fittings, grooved fittings, plain-end compression fittings, flanged connections, and welding. Plain End Pipe Steel pipe when initially formed has flat cut, unpolished ends. This is generally referred to as plain end pipe. Plain end pipe can be connected by compression fittings or push-on fittings, which bite into the pipe to prevent separation. While popular for other building systems, use of plain end pipe and compression or push-on fittings are not used in sprinkler systems due to the relatively high pressures sprinkler systems experience.  Threaded Pipe Perhaps the most common current method of joining fire sprinkler pipe for smaller pipe diameters, threaded pipe makes use of helical crests that screw into a female threaded fitting. To create threaded pipe, a plain-end pipe is cut with a threaded machine decreasing the thickness of the pipe wall. As a result, the areas remaining below and adjacent to the thread become weaker and more susceptible to corrosion breakthroughs with the thinner wall of pipe.  As compared to grooving or welding pipe, the pipe wall thickness must be thicker to accommodate the cut-in threads (ASME B1.20.1) for threaded pipe. NFPA 13 6.5.1.2 (2002-2016 Editions) addresses minimum pipe thicknesses for threaded pipe up to 300 psi, unless the pipe is separately listed for fire sprinkler use:
When connecting threaded pipe, joint compound or pipe tape is applied to the male thread to avoid water leakage. While threading larger pipe was common throughout the early to mid twentieth century, the weight of Schedule 40 pipe and difficulty of turning large diameter threaded pipe makes threading an uncommon choice for larger diameter sprinkler pipe today. Grooved Pipe Grooved pipe is a popular method of pipe joining invented by Victaulic with roots in both World Wars to deliver water and petroleum with faster, more reliable method of pipe connection.  Grooved pipe is formed by either cutting into the pipe (cut groove) or by pressing an indentation into the pipe (roll groove). Cut groove pipe results in a lesser pipe thickness, weakening the pipe and also offering less protection against corrosion. Roll grooving, while keeping the pipe wall thickness, also poses issues in low-sloped dry and pre-action systems as the rolls on the interior side of the pipe create areas to trap water and create an air-water interface for corrosion to occur.  Grooved pipe has a number of inherent advantages. Smaller pipe thicknesses are permitted for grooved pipe, resulting in thinner pipe which makes transporting, carrying, and lifting into place easier. Minimum thicknesses for Grooved Pipe:
With thinner, lighter pipe and easy grooved coupling options, labor can be less difficult and significantly quicker. Welded & Flanged Pipe A less common but additional option for restraining pipe is welding. Pipe can be welded as an outlet - where a welding equipment cuts a hole in one pipe whereafter another pipe segment is held in place and the two are welded together.  Welding has a few advantages - it can be (and often is) performed in a fabrication shop, does not require any additional fittings, and can allow for more custom pipe arrangements. For instance: a 4-inch x 4-inch x 1/2-inch outlet for a pressure gauge connection might be a special order reducing tee (ie: costly); as a welded outlet, it could be quickly and easily welded into place with the outlet easily threaded or grooved. Welding is not limited to outlets, however. "Slip-on flanges" can be welded to the hub side of the flange to a piece of pipe, allowing two flanged fittings to be bolted together with a gasket in-between.  Flanged pipe and fittings are common around fire pump assemblies, as NFPA 20 annex material even notes that "flanges welded to pipe are preferred" despite screwed, flanged mechanical joints or other approved fittings are allowable (NFPA 20 2003-2007 5.13.2.1, 2010-2013 4.13.2, 2016 4.14.2, 2019 4.15.2).
Different installing contractors often have different preferences on fabricating pipe. Personally I've worked with some who prefer to have welded outlets along 21-foot lengths of pipe and groove as much as allowed for a job to use lighter, thinner pipe, including through branch piping. Others prefer some flexibility of threaded pipe to make quick changes in the field and provide a more traditional, tightly-connected threaded system. What do you commonly see? Does your team have preferences for fabrication methods? Discuss this here. Follow the Movement Get these articles, for free, once a week. Follow the movement for better fire protection here. |
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AuthorJoseph Meyer, PE, is a Fire Protection Engineer in St. Louis, Missouri. See bio on About page. Categories
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