1014.1 General — 2025 California Mechanical Code

Boilers and pressure vessels shall be operated and maintained in accordance with requirements for pro

tection of the public established by the Authority Having Jurisdiction in accordance with nationally recognized standards.

The Authority Having Jurisdiction shall notify the owner or authorized representative of defects or deficiencies and properly corrected. Where such corrections are not made, or where the operation of the boiler or pressure vessel is deemed unsafe by the Authority Having Jurisdiction, they shall have the authority to revoke the permit to operate the boiler or pressure vessel. Where the operation of a boiler or pressure vessel is deemed by the Authority Having Jurisdiction to constitute an immediate danger, the pressure on such boiler or pressure vessel shall be permitted to be relieved at the owner’s cost and the boiler or pressure vessel shall not thereafter be operated without the approval of the Authority Having Jurisdiction.

BOILERS AND PRESSURE VESSELS

CONTROL AND LIMIT DEVICE SYSTEM DESIGN11			Required	Required	Required	Required	Required	Required	Required	Required	Required	Per NFPA 85	Per NFPA 85
APPROVED FUEL SHUT- OFF10	APPROVED FUEL SHUT- OFF10	APPROVED FUEL SHUT- OFF10	Not Required	Not Required	Required	Required	Not Required	Not Required	Not Required	Required	Not Required	Per NFPA 85	Per NFPA 85
STEAM PRESSURE AND LOW WATER LIMIT CON- TROLS9	STEAM PRESSURE AND LOW WATER LIMIT CON- TROLS9	STEAM PRESSURE AND LOW WATER LIMIT CON- TROLS9	Required	Required	Required	Required	Required	Required	Required	Required	Required	Per ASME Power Boiler Code, Section 1 and NFPA 85	Per ASME Boiler & Pressure Code & NFPA 85
HOT WATER TEMPERA- TURE AND LOW WATER LIMIT CON- TROLS8	HOT WATER TEMPERA- TURE AND LOW WATER LIMIT CON- TROLS8	HOT WATER TEMPERA- TURE AND LOW WATER LIMIT CON- TROLS8	Required	Required	Required	Required	Required	Required	Required	Required	Required	Per ASME Power Boiler Code, Section 1 and NFPA 85	Per ASME Boiler & Pressure Code & NFPA 85
PRE- PURGING CONTROL7	PRE- PURGING CONTROL7	PRE- PURGING CONTROL7	Not Required	Not Required	Required	Required	Not Required	Not Required	Not Required	Required	Not Required	Per NFPA 85	Per NFPA 85
LOW FIRE START UP CONTROL6	LOW FIRE START UP CONTROL6	LOW FIRE START UP CONTROL6	Not Required	Not Required	Required	Required	Not Required	Not Required	Not Required	Required	Not Required	Per NFPA 85	Per NFPA 85
ASSURED AIR SUP- PLY CON- TROL5	ASSURED AIR SUP- PLY CON- TROL5	ASSURED AIR SUP- PLY CON- TROL5	Required	Required	Required	Required	Required	Required	Required	Required	Not Required	Per NFPA 85	Per NFPA 85
ASSURED FUEL SUP- PLY CON- TROL4	ASSURED FUEL SUP- PLY CON- TROL4	ASSURED FUEL SUP- PLY CON- TROL4	Not Required	Not Required	Required	Required	Not Required	Required	Required	Required	Not Required	Per NFPA 85	Per NFPA 85
SAFETY CONTROL TIMING (NOMINAL MAXIMUM TIME IN SECONDS)	MAIN BURNER FLAME FAILURE3	MAIN BURNER FLAME FAILURE3	90	2-4	2-4	2-4	90	2-4	2-4	2-4	Not Required	Per NFPA 85	Per NFPA 85
SAFETY CONTROL TIMING (NOMINAL MAXIMUM TIME IN SECONDS)	TRIAL FOR MAIN BURNER FRAME	FLAME PILOT	90	15	15	15	90	30	15	60	Not Required	Per NFPA 85	Per NFPA 85
SAFETY CONTROL TIMING (NOMINAL MAXIMUM TIME IN SECONDS)	TRIAL FOR MAIN BURNER FRAME	DIRECT ELECTRIC IGNITION	Not Required	15	15	15	90	30	15	15	Not Required	Per NFPA 85	Per NFPA 85
SAFETY CONTROL TIMING (NOMINAL MAXIMUM TIME IN SECONDS)	TRIAL FOR PILOT	TRIAL FOR PILOT	90	15	15	15	Not Required	Not Required	Not Required	15	Not Required	10 sec Per NFPA 85	Per NFPA 85
TYPE OF PILOT2	TYPE OF PILOT2	TYPE OF PILOT2	Any type	Interrupted or Intermittent	Interrupted or Intermittent	Interrupted	Any type	Interrupted	Interrupted	Interrupted	Not required	Any	None
FUEL INPUT RANGE1 (INCLUSIVE), BTU/H	FUEL INPUT RANGE1 (INCLUSIVE), BTU/H	FUEL INPUT RANGE1 (INCLUSIVE), BTU/H	0 - 400 000	400 001 - 2 500 000	2 500 001 - 5 000 000	Over 5 000 000	0 - 400 000	400 001 - 1 000 000	1 000 001 - 3 000 000	Over 3 000 000	All	12 500 000 or more	Any
FUEL	FUEL	FUEL	Gas	Gas	Gas	Gas	Oil	Oil	Oil	Oil	Electric	Gas, Oil and/or Coal	Heat Recovery Steam Generator
BOILER GROUP	BOILER GROUP	BOILER GROUP	A	B	C	D	E	F	G	H	K	L	M

222 2025 CALIFORNIA MECHANICAL CODE

BOILERS AND PRESSURE VESSELS

FOOTNOTES FOR TABLE 1003.2.1 (continued)

1 Fuel input shall be determined by one of the following:

The burner input shall not exceed the input shown on the burner nameplate or as otherwise identified by the manufacturer.

The nominal boiler rating, as determined by the building official, plus 25 percent.

2 Automatic boilers shall have one flame failure device on each burner, which shall prove the presence of an ignition source at the point where it will ignite

the main burner, except that boiler groups A, B, E, F, and G, which are equipped with direct electric ignition, shall monitor the main burner, and boiler

groups using interrupted pilots shall monitor the main burner after the prescribed limited trial and ignition periods. Boiler group A, equipped with continu ous pilot, shall accomplish 100 percent shutoff within 90 seconds upon pilot flame failure. The use of intermittent pilots in boiler group C is limited to

approved burner units.

3 In boiler groups B, C, and D a 90 second main burner flame failure limit shall be permitted to be applied where continuous pilots are provided on manufac turer assembled boiler-burner units that have been approved by an approved testing agency in accordance with nationally recognized standards approved by

the building official. Boiler groups F and G equipped to re-energize their ignition systems within 0.8 second after main burner flame failure will be permit ted 30 seconds for group F or 15 seconds for group G to re-establish their main burner flames.

4 Boiler groups C and D shall have controls interlocked to accomplish a non-recycling fuel shutoff upon high or low gas pressure, and boiler groups F, G, and

H using steam or air for fuel atomization shall have controls interlocked to accomplish a nonrecycling fuel shutoff upon low atomizing steam or air pressure.

Boiler groups F, G, and H equipped with a preheated oil system shall have controls interlocked to provide fuel shutoff upon low oil temperature.

5 Automatic boilers shall have controls interlocked to shut off the fuel supply in the event of draft failure where forced or induced draft fans are used or, in the

event of low combustion airflow, where a gas power burner is used. Where a single motor directly driving both the fan and the oil pump is used, a separate

control is not required.

6 Boiler groups C, D, and H, where firing in excess of 400 000 Btu/h (117 kW) per combustion chamber, shall be provided with low fire start of its main burner

system to permit smooth light-off. This will normally be a rate of one-third of its maximum firing rate.

7 Boiler groups C, D, and H shall not permit pilot or main burner trial for ignition operation before a purging operation of sufficient duration to permit not less

than four complete air changes through the furnace, including a combustion chamber and the boiler passes. Where this is not readily determinable, five com plete air changes of the furnace, including combustion chamber up to the first pass, will be considered equivalent. An atmospheric gas burner with no mechan ical means of creating air movement or an oil burner that obtains two-thirds or more of the air required for combustion without mechanical means of creating

air movement shall not require purge by means of four air changes, so long as its secondary air openings are not provided with means of closing. Where such

burners have means of closing secondary air openings, a time delay shall be provided that puts these closures in a normally open position for four minutes

before an attempt for ignition. An installation with a trapped combustion chamber shall, in every case, be provided with a mechanical means of creating air

movement for purging. 8 An automatic hot-water-heating boiler, low-pressure hot-water-heating boiler, and power hot water boiler shall be equipped with two high-temperature limit

controls with a manual reset on the control, with the higher setting interlocked to shut off the main fuel supply, except that manual reset on the high-tem perature limit control shall not be required on an automatic package boiler not exceeding 400 000 Btu/h (117 kW) input and that has been approved by an

approved testing agency. An automatic hot-water heating, power boiler, and package hot-water supply boiler shall be equipped with one low-water level limit

control with a manual reset interlocked to shut off the fuel supply, so installed as to prevent damage to the boiler and to permit testing of the control with out draining the heating system, except on boilers used in Group R Occupancies of less than six units and in Group U Occupancies and further, except that

the low-water level limit control is not required on package hot-water supply boilers approved by a nationally recognized testing agency. However, a low water flow limit control installed in the circulating water line shall be permitted to be used instead of the low-water level limit control for the same purpose

on coil-type boilers. 9 An automatic low-pressure steam-heating boiler, small power boiler, and power steam boiler shall be equipped with two high-steam pressure limit controls

interlocked to shut off the fuel supply to the main burner with manual reset on the control, with the higher setting and two low-water-level limit controls,

one of which shall be provided with a manual reset device and independent of the feed water controller. Coil-type flash steam boilers shall be permitted to

use two high-temperature limit controls, one of which shall be manually reset in the hot water coil section of the boiler instead of the low-water level limit

control.

10 Boiler groups C, D, and H shall use an approved automatic reset safety shutoff valve for the main burner fuel shutoff, which shall be interlocked to the pro gramming control devices required. On oil burners where the safety shutoff valve will be subjected to pressures in excess of 10 psi (69 kPa) where the burner

is not firing, a second safety shutoff valve shall be provided in series with the first. Boiler groups C and D using gas in excess of 1 psi (7 kPa) pressure or

having a trapped combustion chamber or employing horizontal fire tubes shall be equipped with two approved safety shutoff valves, one of which shall be

an automatic reset type, one of which shall be permitted to be used as an operating control, and both of which shall be interlocked to the limit-control devices

required. Boiler groups C and D using gas in excess of 1 psi (7 kPa) pressure shall be provided with a permanent and ready means for making periodic tight ness checks of the main fuel safety shutoff valves.

11 Control and limit device systems shall be grounded with operating voltage not to exceed 150 volts, except that, upon approval by the building official, exist ing control equipment to be reused in an altered boiler control system shall be permitted to use 220 volts single phase with one side grounded, provided such

voltage is used for all controls. Control and limit devices shall interrupt the ungrounded side of the circuit. A readily accessible means of manually discon necting the control circuit shall be provided with controls so arranged that where they are de-energized, the burner shall be inoperative.

224 2025 CALIFORNIA MECHANICAL CODE

CALIFORNIA MECHANICAL CODE – MATRIX ADOPTION TABLE