Gritty Sprinkler Fitter

NFPA 13D, sprinklers for one- and two-family dwellings and manufactured homes, for the Minnesota journeyman sprinkler fitter exam. Minnesota pins 13D-2016 (Minn. R. 7511.8000); we map it to 13D-2019. When Minnesota requires house sprinklers (MSFC 903.2.8: R-3 dwelling units of 4,500 sq ft and up, excluding garages) and when 13D is allowed (903.3.1.3); purpose (prevent flashover in the room of origin, help people escape); temperature ratings incl. 2019 high temp; no spare sprinklers; listing exceptions; 175 vs 130 psi pipe and the 80 psi PRV rule; PEX and CPVC; stored water 10 min / 7 min; pumps (1.5 in. off the floor, 240 V); multipurpose systems and the warning sign; water treatment bypass; 5 gpm common pipe add; single control valve; 1/2 in. drain; test connection K-factors; residential heads, sauna high temp, heat source distance table; positioning, fans 3 ft / 5 ft, soffits, shadow areas, bay windows, dry barrel lengths, closets; where heads can be omitted (55 sq ft baths, 24 sq ft closets, garages, attics) and Minnesota's townhouse garage dry head within 5 ft of each door (903.3.1.6.6); freezing options; 15 s dry delivery; 0.05 gpm/sq ft, two design heads, 7 psi; minimum pipe sizes; acceptance tests. App news: the MN Journeyman Exam Prep Android app has enough testers, and its 14-day countdown to going public on Google Play has started. Expect it on the Play Store in a couple of weeks, once Google finishes its review.

Sprinkler identification, temperature ratings and spare sprinklers for the Minnesota journeyman sprinkler fitter exam. NFPA 13 (2016 6.2/8.3, the edition Minnesota pins, mapped to 2019 7.2, 9.4.2 and 16.2) plus NFPA 25-2020: only new sprinklers, no reinstalling (except dry per manufacturer), no reconditioned heads; the SIN (1-2 letters + 3-4 numbers; K-factor, deflector, pressure rating, thermal sensitivity); the K-factor table (K-5.6 100%, K-8.0 140%, K-11.2 200%, threads), CMSA/ESFR K-11.2 minimum; temperature ratings, max ceiling temps and color codes (frame vs. bulb traps); where intermediate and high temp heads go (steam mains, blowoff valves, skylights, attics, show windows, cooking, defrost freezers, 2019 ventless dryer closets, heating duct and unit heater table); 150°F storage minimum; quick response rules; painting, coatings, cellophane bags, escutcheons, no caulk, guards; spare cabinet 6/12/24, wrenches, dated list, cabinet temperature; NFPA 25 annual inspection and replacement rules. App news: the MN Journeyman Exam Prep Android app has enough testers, and its 14-day countdown to going public on Google Play has started. Expect it on the Play Store in a couple of weeks, once Google finishes its review.

Occupancy hazard classification and what it does to your design, for the Minnesota journeyman sprinkler fitter exam. NFPA 13 (2016 ch.5/11, the edition Minnesota pins, mapped to 2019 ch.4/19): classifications are for sprinkler design only; light hazard, ordinary group 1 (8 ft stockpiles), ordinary group 2 (12 ft / 8 ft), extra hazard group 1 (dust, lint) and group 2 (liquids, shielding); the annex example lists (churches, hospitals, distilleries, mercantile, post offices, repair garages, car stackers). Density/area curves (any single point, 1,500/2,500 sq ft minimums, spray only, no QR in extra hazard), QR area reduction, +30% dry/double interlock and sloped ceilings, high-temp and 2019 K-11.2 reductions, 3,000 sq ft concealed-space rule, room design method (8 in. lintel), special design areas, hose stream and duration tables, pipe schedule, residential sprinklers in NFPA 13, 15 ft adjacent hazard rule, 400 sq ft rule. Minnesota: 903.3.1.4 undetermined use = OH2 over 3,000 sq ft, 903.3.1.5 chemistry labs and wrestling/gymnastics rooms, 903.3.1.6.1 fire chief can modify hose streams. App news: the MN Journeyman Exam Prep Android app has enough testers, and its 14-day countdown to going public on Google Play has started. Expect it on the Play Store in a couple of weeks, once Google finishes its review.

Pipe, fittings and joining methods, every rule a Minnesota journeyman sprinkler fitter needs for the exam. NFPA 13 (2016 chapter 6, the edition Minnesota pins, mapped to 2019 chapters 7 and 16, with 2025 checks): the pipe standards table (ASTM A795, F442 CPVC, lead-free solder, BCuP-3/4 brazing filler), underground pipe 24 in. into the building, Schedule 10 for welded or roll-grooved steel (0.134/0.188/0.330 in. for 6/8-10/12 in.), Schedule 40 under 8 in. and Schedule 30 at 8 in. and up for threaded or cut-grooved pipe, threading thin wall only when listed, copper Type K/L/M, brass and stainless limits, bend radii (6 and 5 diameters for Sch 40 and copper, 12 for other steel), CPVC listing and compatibility rules, the 400 sq ft ordinary hazard room and the 2019 dwelling garage rule, pipe marking on every piece over 2 ft. Fittings: cast iron and malleable iron pressure limits, extra-heavy over 175 psi, bronze 200/400 psi, screwed unions 2 in. max, one-piece reducers vs. bushings, extension fittings (K-8.0, LH/OH, 2 in.). Joining: threads to ASME B1.20.1, joint compound on male threads only, shop welding by default, welding in place per NFPA 51B, no welding in rain/snow/sleet/high wind, no torch cutting or welding to modify or repair (2016/2019), throat thickness, flange and bracing tab welds, the 9-item welding list (retrieve the coupons), welder qualifications and marks, 12-gauge welding stud limit, grooved couplings and gaskets listed for dry service, brazed copper by default and when solder is allowed, solvent cement before heads, gasketed outlet fittings, removing burrs. Help us get the MN Journeyman Exam Prep Android app out of closed testing: join the tester group at https://groups.google.com/g/mn-journeyman-exam-testers, then opt in at https://play.google.com/apps/testing/com.mnfireexamprep.app.

Antifreeze sprinkler systems, every rule a Minnesota journeyman sprinkler fitter needs for the exam. NFPA 13 (2016 section 7.6, the edition Minnesota pins, side by side with 2019 section 8.6, with 2025 checks): state and local health regulations, ESFR only with a listed head (premixed propylene glycol exception), draining pendent systems after a water hydro (or testing with the antifreeze), the remote-system placard at the riser and the main-valve placard (type and brand, concentration, volume), listed solutions only for new systems and why (FPRF tests: ignition of the discharge spray). Concentration limits: NFPA 13 annex 48% glycerine / 38% propylene glycol for approved existing systems, NFPA 13D-2016 50%/40% for existing systems and 48%/38% for a specific area, NFPA 25-2020 30% propylene glycol / 38% glycerine (up to 40%/50% with a deterministic risk assessment) for pre-2012 systems until 9/30/2022, CPVC glycerine only. Piping: the 5 ft drop, the 1/32 in. hole in the check valve clapper (vs. 3/32 freezer and 1/8 dry), backflow preventers and listed expansion chambers, the 1/2 in. relief valve for systems of 40 gal or less, the three-condition automatic exception, drain/test connection at the most remote point plus one per 100 gal over 150 gal. NFPA 25-2020 annual test before freezing weather: identify the solution, drain unknown or non-permitted mixes, sample top/bottom/remote/supply, hydrometer or refractometer. NFPA 13D annual test and riser tag contents. Help us get the MN Journeyman Exam Prep Android app out of closed testing: join the tester group at https://groups.google.com/g/mn-journeyman-exam-testers, then opt in at https://play.google.com/apps/testing/com.mnfireexamprep.app.

Dry pipe and preaction systems (plus a little deluge), every rule a Minnesota journeyman sprinkler fitter needs for the exam. NFPA 13 (2016, the edition Minnesota pins, side by side with 2019, with 2025 checks): where dry systems belong, Minnesota's flammable-liquid storage rule (wet, deluge or preaction only, Minn. R. 7511.5704) and the compact-storage ban on dry and double interlock. Dry valve rooms: lighted, heated, permanent heat, no heat tape; the five required gauge locations; high water level protection on differential vs. low differential valves; priming water and water columning. System size: 60 seconds, 500 gal without a quick-opening device, 750 gal with one, the delivery-time table (1 head/60 s light, 2/50 ordinary, 4/45 extra, 4/40 high piled), test manifolds, and the 15-second dwelling-unit rule. Pipe-volume calculator math, 1/8 in. holes in subdividing check valves, no gridded dry systems, accelerators vs. exhausters. Air and nitrogen: 30-minute restore (60 min below 5°F), 1/2 in. air connection above the priming water, relief valve at least 10 psi over system air (not 50), system air 20 psi over calculated trip, the 5.5 cfm at 10 psi compressor exception, dedicated air maintenance devices, cord-and-plug compressors. Uprights, dry pendents and the 40°F rule, the wet-system barrel-length trap, Minnesota's townhouse-garage dry head within 5 ft of each door. Pitch 1/2 in. and 1/4 in. per 10 ft (1/2 and 1/2 in freezers), aux drains, drum drips (two 1 in. valves and a 2 x 12 in. nipple), 1 in. tie-in drains, the low point drain sign, paddle switches wet-only, trip test connections. Preaction: single interlock, non-interlock, double interlock, 1,000 heads per valve, 500 gal/60 s double interlock sizing, more than 20 heads supervised, 7 psi supervising air, 15 psi relief exception, no gridding, 30 percent design area increase for dry and double interlock. Deluge supervision and calcs, combined pier systems (600/275 heads, two 6 in. valves, 1 minute per 400 ft, 3 minutes max), 3/32 in. freezer check valves. Acceptance: 40 psi air test for 24 hours with 1.5 psi max loss, modification tests (40 psi/2 h/3 psi or 4 hours air off), clapper position, trip test timing, and Minnesota's definition of a trip test as an "inspection" (Minn. R. 7512.0100). Help us get the MN Journeyman Exam Prep Android app out of closed testing: join the tester group at https://groups.google.com/g/mn-journeyman-exam-testers, then opt in at https://play.google.com/apps/testing/com.mnfireexamprep.app.

Fire department connections, every rule a Minnesota journeyman sprinkler fitter needs for the exam. Minnesota State Fire Code 2020 Section 912: location approved by the fire code official, street-side visibility, the existing-building FDC locator sign (6 in. letters, 2 in. words), Minnesota's 18 in. to 4 ft connection height (Minn. R. 7511.0912), access and the gate exception, locking caps, the 36 x 36 x 78 in. clear space, vehicle impact protection, 1 in. raised-letter signs, backflow and NFPA 25 records. Minnesota's other FDC amendments in 7511.0903: the 25 ft maximum pipe between the check valve and the inlet (free-standing exception) and the exterior audible and visible alarm above the FDC. NFPA 13 (2016/2019, with 2025 checks): when an FDC isn't required (and why 'more than 20 heads' is the alarm rule, not the FDC rule), 13R's 2,000 sq ft or multi-story trigger, two 2-1/2 in. NH inlets and the single-inlet 3 in. riser exception, 4 in./6 in. pipe size, wet/dry/preaction/deluge tie-in points, no branch lines, no fire pump suction side, no shutoff valve, automatic drains, the 150 psi pressure-sign wording trap. NFPA 14 standpipe FDCs: one inlet per 250 gpm, two per zone in high-rises, 100 ft to a hydrant. Hydro tests: acceptance same as the system, NFPA 25 quarterly 10-point inspection, annual interior with locking caps, 150 psi for 2 hours every 5 years, and component replacement tests. Help us get the MN Journeyman Exam Prep Android app out of closed testing: join the tester group at https://groups.google.com/g/mn-journeyman-exam-testers, then opt in at https://play.google.com/apps/testing/com.mnfireexamprep.app.

Minnesota State Fire Code 2020 Section 904, the systems that aren't sprinklers but land on a sprinkler fitter's plate anyway. Minnesota's amended 904.1.1 service-personnel certificate, why an alternative system can't be used to claim sprinkler trade-offs, Type I hood protection, actuation, interlocks, pre-discharge alarms, acceptance inspection and testing, wet- and dry-chemical six-month tests, CO2 and halon container and hose test numbers, water mist, and the commercial cooking package: UL 300, the pull station 10 to 20 feet from the exhaust system and 42 to 48 inches high, 40 lb and 14 in limits, fuel and power shutdown with manual reset, the separate indicating valve for sprinkler-protected cooking, UL 199E fryer sprinklers, six-month service, annual fusible link and head replacement, and domestic cooking protection in I-1, I-2 and Minnesota R-2 congregate living. Every number read from the 2020 MSFC and Minn. R. 7511 on revisor.mn.gov. Help us get the MN Journeyman Exam Prep Android app out of closed testing: join the tester group at https://groups.google.com/g/mn-journeyman-exam-testers, then opt in at https://play.google.com/apps/testing/com.mnfireexamprep.app.

A listener handed us his LICENSING EXAM - PREP QUESTIONS study sheet, and we go through every line of it with the books open. NFPA 13 deflector position and how to measure below flat and sagging batt insulation; obstructed vs. unobstructed construction and the concrete tee rule, which picked up a 30 in. stem-depth cap in the 2025 edition; the Three Times Rule, its 24 in. cap and its exceptions; standard sidewall spacing, back-to-back lintels, soffits and the 4 to 6 in. deflector zone; main drain sizes and trapped-water auxiliary drains; unsupported end lengths, armovers and the over-100 psi rule; and the hanger table for steel, threaded lightwall and CPVC. Then NFPA 25: inspection vs. testing vs. maintenance, the annual, 3-year and 5-year tasks in Tables 5.1.1.2 and 13.1.1.2, and acceptance testing vs. ITM. Each section number is given three ways: the 2016 number on the sheet (the edition Minnesota still pins), the 2019 number, and the 2025 number where we could verify it. We also flag the places where the sheet is wrong or out of date. Minnesota rules checked on revisor.mn.gov. Help us get the MN Journeyman Exam Prep Android app out of closed testing: join the tester group at https://groups.google.com/g/mn-journeyman-exam-testers, then opt in at https://play.google.com/apps/testing/com.mnfireexamprep.app.

The installation rules in Minnesota State Fire Code 2020 Section 903.3 that nobody reads until an inspector reads them to you. Where quick-response or residential sprinklers are mandatory, the four-foot kiosk rule and the three-foot clearance over combustible fiber piles, automatic actuation, water supplies and backflow, adjusting a hydrant test for seasonal and daily pressure swings, residential combination services, hose threads, FDCs, and the whole limited area sprinkler system package (six sprinklers per fire area, Light Hazard or Ordinary Hazard Group 1 only, standpipe or plumbing supply, supervised or secured valves, hydraulic calcs). Plus the exempt-location list and what Minnesota added to it. Every number read from the 2020 MSFC and Minn. R. 7511 on revisor.mn.gov. Help us get the MN Journeyman Exam Prep Android app out of closed testing: join the tester group at https://groups.google.com/g/mn-journeyman-exam-testers, then opt in at https://play.google.com/apps/testing/com.mnfireexamprep.app.