2.1 248 CMR 4.00/5.00, Materials & Components

2.1 248 CMR 4.00/5.00, Materials & Components

Quick Answer: In Massachusetts the Fuel Gas Code is 248 CMR 4.00 through 8.00. Everyday building gas piping is NFPA 54-2012 as modified by 248 CMR 5.00. Default pressure is not over 0.5 PSIG (14 inch water column). Galvanized pipe is prohibited. Listed gas cocks and ball valves, Board Product-accepted materials, and a 48-inch / 0.5 PSIG connector limit are the Massachusetts overlay you must know on top of NFPA 54 Chapter 5.

This OpenExamPrep chapter is independent teaching for the Massachusetts journeyman plumber exam. It explains who writes the rule and which exam it helps you study. It is not a Board publication and it does not claim official approval.

How Massachusetts actually writes the fuel gas code

Open the live pages, not a study-guide rumor. 248 CMR 4.00 and 248 CMR 5.00 (both listed as 04/30/2021, Mass. Register #1442) are the current fuel-gas adoption and NFPA 54 amendments. The Board’s policies, regulations, and statutes list is the download hub for the same PDFs.

248 CMR 4.02 defines NFPA 54 as the 2012 Edition of the National Fuel Gas Code and NFPA 58 as the 2011 Edition of the National Liquefied Petroleum Gas Code (including the 2010/2011 errata named in 4.02). 248 CMR 4.00 through 8.00, collectively, govern fuel-gas piping, utilization equipment, and related accessories in the Commonwealth.

248 CMR 4.03(1) is the sentence PSI-style items harvest: for most installations the Board adopts NFPA 54 as modified by 248 CMR 5.00. Jurisdiction runs from the point of delivery to the connection at each gas utilization device.

248 CMR 4.03(1)(b) then caps ordinary systems: all gas piping systems shall be low pressure, not in excess of 0.5 PSIG or 14 inch water column. You may exceed that only when the system is designed and installed under 248 CMR 5.05(4)(B) — the elevated-pressure path that requires a Massachusetts registered professional engineer except for the two narrow exceptions in 5.05(4)(B)5.

Acetylene, hydrogen, ammonia, carbon monoxide, oxygen, and nitrogen are not run under NFPA 54. 248 CMR 4.03(1)(c) and 4.03(6) send those gases to an engineer-designed system with stamped drawings before a permit is issued.

Order of precedence and the CIB numbering trap

When documents conflict, 248 CMR 4.04 ranks them from highest priority:

1. 248 CMR 4.00
2. NFPA 85 as modified by 248 CMR 4.00
3. NFPA 86 as modified by 248 CMR 4.00
4. 248 CMR 7.00 Large Gas Utilization Equipment
5. NFPA 54 as modified by 248 CMR 5.00
6. NFPA 58 as modified by 248 CMR 8.00

That last line is the live citation. Mass.gov publishes 248 CMR 8.00: Amendments to NFPA 58. Some Candidate Information Bulletin text still lists “248 CMR 6.00” as the NFPA 58 amendment chapter. 6.00 is not the live Mass.gov LP amendment chapter. Study 8.00. 248 CMR 8.03 even repeats the product-acceptance overlay for listed LP equipment. Do not memorize a retired number on exam day.

248 CMR 4.05 allows an alternative material or method only if it is acceptable to the Board and supported by evidence. That is not a field “judgment call.” It is Board equivalency.

Product acceptance is not optional

NFPA 54 talks about “listed” equipment. Massachusetts adds a second gate.

• 248 CMR 5.03(2) (modifying NFPA 54 3.2.4): listed equipment must also meet product acceptance in 248 CMR 3.00.
• 248 CMR 5.09(1) replacing NFPA 54 9.1.1: only products and materials that meet 248 CMR 3.04(1) Board Required Product-acceptance may be used in gas-fitting work, unless the Board waives acceptance under 3.04(1)(h).
• 248 CMR 5.09(3) replacing 9.1.1.3: unlisted appliances, equipment, and accessories need a Board variance.
• 248 CMR 5.03(3) and 5.04(1)–(2) delete NFPA 54’s “qualified agency” language and substitute licensee. The person on the permit is a Massachusetts licensee, not a vague “agency.”

248 CMR 3.04(1) is blunt: manufacturers apply item-by-item; the Board keeps the Product-accepted list; do not install a product that is waiting on a vote. Permanent old “product-approvals” are null. On the exam, “UL listed, so I can install it in Massachusetts” is the wrong answer unless the item is also Product-accepted or waived.

248 CMR 5.04 adds 4.4 Workmanship: installations must meet the code, follow good mechanical practice, stay straight, level, or plumb with the required grade or slope, must not damage structural integrity (see 780 CMR for building work), and must not be installed so that other gas appliances cannot be removed and replaced.

Steel, fittings, and what Massachusetts forbids

NFPA 54-2012 Chapter 5 is still the materials catalog, but 248 CMR 5.05 rewrites the Massachusetts parts you will be tested on.

Steel and wrought-iron pipe remain the ordinary interior fuel-gas materials. 248 CMR 5.05(6) adds 5.6.2.2.1 Welding of Steel and Wrought Iron Pipe. Welding itself is not “gas-fitting,” but a licensee may use welded pipe and fittings only when they meet NFPA 54 5.6.2.2 and the Massachusetts test rules:

• Operating pressure ≤ 70 PSIG: inspector visual weld inspection, plus a pressure test (systems ≤ 10 PSIG tested to the greater of 3 PSIG or ten times operating pressure; systems > 10 and ≤ 70 PSIG tested at 100 PSIG). Duration is one hour per 100 feet or fraction, minimum one hour, maximum 24 hours.
• Operating pressure > 70 PSIG: full-penetration welds, 100% X-ray or UT (socket welds get magnetic-particle or other NDT), system test at least 1.25 times working pressure, inspector-witnessed, minimum one hour. Failed welds that are repaired are restenciled with the retest date in ½-inch white lettering.

Two bright-line Massachusetts size and pressure rules sit next to that welding section:

• 248 CMR 5.05(4)(B)3: when maximum design operating pressure exceeds 5 PSIG, all piping shall be welded in accordance with 5.6.2.2.1.
• 248 CMR 5.05(9) replacing 5.6.8.4(1): pipe and fittings in excess of four inches in diameter shall be welded.

248 CMR 5.05(7) is a one-sentence exam favorite: 5.6.2.7 Galvanized. Galvanized pipe shall not be used. Do not “protect” a buried steel line by choosing galvanized. Massachusetts banned the material. Underground corrosion protection is coating, wrapping, and cathodic systems under NFPA 54 Chapter 7 (see Section 2.3) — not zinc-coated pipe.

Cast iron. 248 CMR 5.05(10) deletes “or cast iron” from NFPA 54 5.6.8.4(2). 248 CMR 5.05(11) replacing 5.6.8.4(5) then limits the leftover use: cast iron is only permitted for flanges, valves, strainers, and filters. You do not build the gas piping run itself out of cast-iron pipe.

Other fittings. 248 CMR 5.05(12) new 5.6.8.5: metallic joints and fittings that do not otherwise meet the section may still be used if the Board approves them or they have met 248 CMR 3.04(1) product acceptance. Field improvisation is not a listed method.

Large systems. 248 CMR 5.05(1) replacing 5.1.1: piping systems over 5,000,000 BTU/hr require a Massachusetts PE design, stamped drawings before the permit, a written statement from the serving gas supplier that volume, pressure, and demand can be met (including existing load), and a PE certification after installation that the work matches the drawings. The inspector checks 248 CMR 5.00 compliance; the inspector does not become the design engineer.

Dual fuels in one building. 248 CMR 5.05(2) new 5.1.3: natural gas and undiluted propane in the same building need written permission from local fire officials and applicable utilities, plus labels at least every ten feet, at every change of direction, on each side of a wall/ceiling penetration, and at every shutoff. Natural gas labels are yellow; propane labels are light green; lettering is black, sized at least to the pipe diameter, and need not exceed two inches on larger pipe.

Valves, sediment traps, unions, and connectors

Manual shutoff valves — 248 CMR 5.05(14) replacing NFPA 54 5.12. Acceptable devices are listed gas cocks and ball valves. They must have clearly indicated open and closed positions and rigidly secured stops at both extremes of rotation, be marked with the manufacturer’s name or trademark, and use a corrosion-resistant handle where the atmosphere or contact material is corrosive. A random unlisted “gas valve” from a bin is not a Massachusetts shutoff device.

Sediment traps (drip legs at the appliance). 248 CMR 5.09 rewrites connectors, product acceptance, and several appliance rules; it does not replace NFPA 54-2012 9.6.7. Leave the model-code sediment trap in place: install it downstream of the appliance shutoff, as close to the appliance inlet as practical, typically a tee with a capped nipple in the bottom opening of the run. Illuminating appliances, ranges, clothes dryers, decorative fireplace appliances, and outdoor cooking appliances are the usual NFPA 54 exceptions that do not require that trap. A piping drip at a low point of a run (to collect condensate) is a different fitting from the appliance sediment trap. Do not omit the trap on a furnace, boiler, or water heater because you already have a drip at the meter.

Unions and replacement access. 248 CMR 5.04 4.4(d) and 5.09(8) (clearance language added to 9.2.1) require the piping arrangement to allow total replacement of the appliance. Practically, that means an accessible union or listed connector between the shutoff and the appliance so the unit can come out without cutting the building piping. 248 CMR 5.09(11) extends the same “do not block replacement” rule to the piping covered by NFPA 54 9.6.8.

Appliance connectors — 248 CMR 5.09(9) new 9.6.1.4:

• Maximum length 48 inches, except connectors under NFPA 54 9.6.1(4) or 9.6.1.1.
• Not for gas pressure in excess of 0.5 PSIG (14 inch water column).
• Not reused, except when you disconnect and reconnect the original appliance for servicing.
• 248 CMR 5.09(10) new 9.6.3.5: flexible hoses for portable/mobile industrial appliances shall not exceed 20 feet.

CSST preview only (full chapter later)

248 CMR 5.05(8) replacing 5.6.3.4 is long. Memorize the Massachusetts gates now; a later chapter covers strike plates, rooftop supports, and bonding.

• Fittings and accessories must be that CSST manufacturer’s parts. Installers need manufacturer training/certification acceptable to the Board.
• Do not connect CSST to an exterior meter. Terminate at the foundation with a termination fitting; run steel to the meter, rigidly supported.
• CSST shall not be used as a flexible appliance connector downstream of the appliance shutoff device.
• Size and install CSST at a maximum 14 inch water column (0.5 PSIG).
• Underground CSST belongs in a load-rated sleeve with liquid-tight ends, warning tape no more than 6 inches below grade, and 18 inches of cover from the top of grade (see Section 2.3).

248 CMR 5.05(5) new 5.5.1.1 covers gas pressure boosters (Product-accepted, utility written authorization, check valve and manual-reset low-pressure switch, regulator immediately downstream unless integral, vibration isolation, ventilated accessible location). Boosters are not a substitute for ignoring the 0.5 PSIG default.

Massachusetts material checklist

Keep the official 4.00/5.00 PDFs from Mass.gov at your bench while you study. Do not substitute a later national NFPA 54 edition for the 2012 text Massachusetts still adopts.