I just wanted to take a quick moment and thank you for the great response to this three day launch of the Sprinkler Database.
If you haven't checked it out already - the deal for the Sprinkler Database is here. I look forward to continuing to create helpful tools to help you do exceptional work, and the launch of the database is one way that helps me keep those efforts going. Have a great weekend and a Happy Easter, thank you! It's almost here! The MeyerFire Sprinkler Database goes live tomorrow at 9am Central. Check out more detail about our long-awaited project with our video: Can't see the video? View it here. See all the details at www.meyerfire.com/sprinkler.
Estimating Pipe Sizes for Sprinkler Systems
Occasionally when designing fire sprinkler systems I'm interested in approximately sizing a specific run of pipe early in a project. That point of interest is often an underground service entry, a main for coordination, or even standpipes. Prior to doing a complete set of hydraulic calculations, running a quick calc using the Hazen-Williams formula can help give an order of magnitude pressure loss that is helpful with initial sizing. Here's the calculator I use for these estimates. Don't see the tool below? See it here. Example: Underground Service Main Sizing Consider a new project with an Ordinary Hazard Group II fire sprinkler system. What should the underground service size be? A 4-inch fire main can be permitted under special circumstances (see NFPA 13 2002 Section 15.1.3, 2007-2010 23.1.3, 2013-2016 24.1.3). A 6-inch fire main is common. Is an 8-inch necessary? If the length of the service main is 10 feet, my answer can often be quite different than if the service main is 1,000 feet. For this exercise I often run a quick calculation to judge the pressure loss in this single pipe as opposed to running calculations for a full system, to get order of magnitude pressure loss. Let's assume a long service main length of 750 feet. Hazen-Williams Formula NFPA 13 stipulates the Hazen-WIlliams formula be used for pipe friction loss calculations for systems other than antifreeze (NFPA 13 2002 Section 14.4.2.1, 2007-2010 22.4.2.1, 2013-2016 23.4.2.1). The Hazen-WIlliams formula, while generally considered conservative, only requires the flow, friction loss coefficient (or C-Factor), and the actual internal diameter of the pipe. Estimating Flow for a Sprinkler System For an Ordinary Hazard Group II example, I can roughly estimate the flow for the system simply based on density and area (assuming the density/area calculation approach). A density of 0.20 gpm/sqft over the most remote 1,500 sqft begins to look like:
Approximate Flow = Density x Area x Overflow Rate + Hose Allowance
Approximate Flow = (0.20 gpm/sqft) x (1,500 sqft) x (1.3) + (250 gpm) Approximate Flow = 640 gpm
Why include the Overflow Rate? Naturally a fire sprinkler system is not going to be perfectly balanced.
While my most remote sprinkler can be calculated at exactly 7 psi and it's k-factor that throws exactly 0.20 gpm/sqft, the feed to that sprinkler will have friction loss. Due to that loss, the adjacent sprinkler will experience a slightly higher pressure than 7 psi and thus will throw slightly more water. This process repeats where sprinklers closer to the riser will provide more than the stipulated density. For order-of-magnitude estimates, I've found that a 30% overflow will be generally close to the final flow result. Pipe Schedule The pipe thickness affects the actual internal diameter of the pipe, so I've included it here. I typically will use Schedule 40 pipe for sizes 2-inch and smaller (so that they may have threaded ends), but I've left the schedule type open to users as I know these preferences can vary. C-Factors The C-Factor relates to the friction-loss due to the surface of the interior of the pipe. NFPA 13 stipulates C-Factors for fire sprinkler systems depending upon the type of system and pipe material. These can be found in NFPA 13 2002 Table 14.4.4.5, 2007-2010 Table 22.4.4.7, 2013 Table 23.4.4.7.1, 2016 Table 23.4.4.8.1. Note that important and impactful changes to the c-factors occurred in the 2013 edition for use of galvanized steel, which has been found to accelerate corrosion by focusing the corrosive action at specific weak points in pipe. Friction Losses With only a few inputs (Flow, Pipe Thickness, C-Factor, and Length of Pipe) you'll now have a comparison of pressure loss across a handful of pipe sizes. Punch in 640 gpm, a Global C-factor of 140 for underground pipe, and a 750 foot pipe length to test this example. If there is plenty of water at high pressure available to the site, perhaps a 48 psi drop on the service entry could be tolerable and a 4-inch main could be used where it meets other NFPA 13 requirements. For the vast majority of projects I cover this loss (48 psi) would not be acceptable. The 6-inch service main shows a pressure loss of under 7 psi, and an 8-inch shows under 2 psi loss. Depending on the water to the site, either of these begin to look much more reasonable. The Friction Loss Calculator This tool is designed to give quick-comparisons of pressure loss for a run of pipe and compare it against other pipe sizes. Do you get these free weekly articles? If not, subscribe here. I'll be posting the weekly article tomorrow but before then I have a question and a favor.
Over the past two years I've been working on a long-awaited resource involving literally hundreds of hours of research and development, but before I wrap up the project I have just one question that will help create a better resource: Learn more and provide input with my quick one-question survey here. How do we best learn design, installation and inspection techniques? Repeated exposure to projects, designs, or input from others. In next week's post we'll debut our first Design Challenge, where we'll reveal a small portion of a building with details. Sprinkler designers (of any age and any location) can propose how he or she would design the system for the proposed building. Now, here's where installers, plan reviewers and inspectors come in - We'll then take the top few submissions and post them against each other in the following week for a full-on debate about the pros and cons of each submission. After a vote, the creator of the winning design will be revealed and featured on our site. Step 1: Next Week: Building Area Revealed & Design Submissions Accepted Step 2: Following Week: Design Submissions Posted, Debate Ensues & Votes Tallied Step 3: Winner Revealed Are you the hotshot designer? Are you the experienced installer? Are you interested in what frustrates plan reviewers or inspectors? Look for our post next week when we reveal the first Design Challenge.
Showcase your job opportunity to our active community of fire protection professionals (designers, engineers, inspectors, review authorities, and more). Our emails are read over 3,000 times monthly, and our site regularly brings over 35,000 page views each month (38,485 in August and 40,693 in September), all reaching professionals in the fire protection industry. This offers a great opportunity to reach a tremendous audience with your job opportunity. We're excited about this new outlet where we hope to serve both job hunters and suppliers. As a launch offer, the first 15 subscribers who checkout using coupon code JOBS2017 will get a free listing. Post your job opportunity and find more information here. You can also see all job listings with us here: Job Board.
We are very excited to announce that we are launching new platform for Daily Discussion! Starting Monday of next week, we will anonymously post open ended-questions that you submit. The technical questions will be distributed to our active community just as the PE Problems are now, and anyone willing to share their expertise will be invited to partake in the discussion. Our hope is that over time we provide opportunities for experts around the country and around the world to weigh in on and learn from the active discussions surrounding the daily questions. We've kicked around various forms of the concept ever since we debuted the daily PE Problems a few years ago, but the interest and feedback gathered since we started has encouraged us to find ways to bring new content and better engage with the sharp, engaging audience that we hear from regularly. Ready to submit a question? They can be anything in fire protection, from fire alarm to sprinkler, life safety to passive fire protection, theory to application. All questions are published anonymously: Do you follow our Blog, but not the daily questions? You can update your subscription to include both our Weekly Blog posts as well as our Daily Questions here: Know a colleague who might benefit or be interested in this? Recommend us to a friend.
We are very excited to announce that the MeyerFire 2017 PE Prep Guide is now available in our Store or on Amazon! The 2017 Edition improves upon the highly-rated 2016 PE Prep Guide with all internal references updated to the 2017 PE Exam specifications (including the 5th Edition of the SFPE Handbooks), has our top exam-passing strategies based on interviews of past examinees, and has one-hundred additional peer-reviewed practice problems alongside the full-length practice exam. Read more about the 2017 PE Prep Guide including feedback received from buyers of the 2016 Edition. We are excited to announce that the 2016 MeyerFire PE Prep Guide has launched! Content The 2016 Prep Guide This Prep Guide is specifically designed to help you pass the 2016 Fire Protection Principles of Engineering (PE) Exam. It contains: + Over 150 of the most important formulas for the exam + Specific page references to 2016 referenced materials for variables, formulas, and example problems + Symbols list and unit conversion table + A full-length, 80 question, peer-reviewed sample PE exam with thoroughly worked solutions This guide does not contain introductory and overview learning material which is already available within the required reference materials. Instead, this prep guide provides the most critical formulas and practice to help you efficiently prepare for the exam and quickly capture solutions on the exam itself. Feedback Received We sent a survey to every customer of ours from 2015: 80% of respondents said they used the formula sheet on at least half of actual exam problems and every respondent (100%) said they would recommend the MeyerFire Formula Sheet to a friend. Here's what they said: "More complete and better organized than other formula sheets available online." "Saves you time." As compared to other formula sheets: "Much more thorough, more helpful." "Much more extensive explanation of the variables." "Very well laid out." "Great explanation of the variables." "Helps on the exam and while studying." "Using this sheet as a starting point, I spent a lot less time cobbling together these formulas and cross references and in turn spent more time studying and getting comfortable with my reference material." Launch Special You can find the Prep Guide either on Amazon, and our Online Store. The best price available is only at www.meyerfire.com. |
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+ Unsubscribe anytime AUTHORJoe Meyer, PE, is a Fire Protection Engineer out of St. Louis, Missouri who writes & develops resources for Fire Protection Professionals. See bio here: About FILTERS
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