CMC · California Mechanical Code
Decorative appliances for installation in vented fireplaces — prohibitions and installation
For homeowners: use only a listed decorative gas appliance in a working, vented masonry or factory-built fireplace made of noncombustible materials, follow the manufacturer’s instructions, don’t add a thermostat, and don’t install in bedrooms/bathrooms unless the room meets the CMC volume requirement or in certain healthcare/correctional occupancies (see **§ 911.1–§ 911.3**).
Last reviewed: July 6, 2026
What the code requires — 2–4 sentences
Decorative gas appliances installed in vented fireplaces must be listed to ANSI Z21.60/CSA 2.26 and installed only in a proper vented fireplace with a working chimney flue constructed of noncombustible materials. They must not be thermostatically controlled. These fundamental requirements are stated in § 911.1 and § 911.3 of the California Mechanical Code (CMC) and must be installed per their listing and the manufacturer’s instructions.
The simplest rule: use only a listed decorative appliance in a vented, noncombustible fireplace with a working chimney flue, follow the listing/manufacturer instructions, and do not add thermostatic control. § 911.1, § 911.3.
Requirements in detail
Applicability / product listing
- The appliance must be listed in accordance with ANSI Z21.60/CSA 2.26. See § 911.1.
- In plain English: choose a product that bears the appropriate listing mark and documentation for use as a decorative appliance in a vented fireplace. § 911.1.
Where they are prohibited
- Decorative appliances for vented fireplaces are prohibited in:
- Bathrooms and bedrooms, unless the room meets the required volume per § 701.4 (see note below). § 911.2.
- Any hospital, skilled nursing facility, intermediate care facility, or correctional treatment center (a vented decorative appliance shall not be located in these occupancies). § 911.2.
Note: § 911.2 refers to Section 701.4 for the required room volume threshold for bedrooms/bathrooms; the precise numeric threshold in § 701.4 was not included in the retrieved text and must be checked directly in § 701.4 of the CMC.
Installation requirements
- Must be installed only in a vented fireplace that:
- Has a working chimney flue, and
- Is constructed of noncombustible materials. § 911.3.
- Thermostatic control is not allowed on these appliances. § 911.3.
- A listed decorative appliance must be installed in accordance with its listing and the manufacturer's installation instructions. § 911.3.1.
Decision‑relevant summary table
| Decision factor | What the code requires | Code reference |
|---|---|---|
| Product listing | Appliance must be listed to ANSI Z21.60/CSA 2.26 | § 911.1 |
| Allowed room types | Not allowed in bathrooms or bedrooms unless room meets required volume; also not allowed in hospitals/skilled nursing/intermediate care/correctional treatment centers | § 911.2 |
| Fireplace construction | Must be a vented fireplace with a working chimney flue and noncombustible materials | § 911.3 |
| Controls | No thermostatic control permitted | § 911.3 |
| Installation authority | Install per listing and the manufacturer’s instructions | § 911.3.1 |
Exceptions & special cases
- Bedrooms/bathrooms: the only allowed exception for those spaces is if the space meets the required volume specified in § 701.4; the CMC text retrieved here refers to § 701.4 but the numeric threshold was not included in the retrieved excerpt, so confirm the exact volume requirement in § 701.4 before permitting installation in those rooms. § 911.2.
- Occupancy exclusions are absolute in the listed healthcare and correctional facilities — a vented decorative appliance is not permitted in those occupancies. § 911.2.
Common mistakes
- Installing an unlisted product or one not listed to ANSI Z21.60/CSA 2.26 for this use — violates § 911.1.
- Installing a decorative appliance in a bathroom or bedroom without first verifying the room meets § 701.4 volume requirements — violates § 911.2.
- Installing in an occupied healthcare or correctional facility — prohibited by § 911.2.
- Placing the unit in a fireplace whose flue is blocked or inactive, or in a firebox built of combustible materials — violates § 911.3 (requires a working flue and noncombustible construction).
- Adding a thermostat or other automatic temperature control to a decorative vented appliance (thermostatic control is disallowed). § 911.3.
- Ignoring the appliance listing and the manufacturer’s installation instructions — § 911.3.1 requires installation per listing/manufacturer instructions.
Worked example — concrete scenario
Scenario: You have a masonry fireplace in a living room and want to install a decorative gas log appliance that is listed to ANSI Z21.60/CSA 2.26. The appliance has a rated input of 20,000 Btu/hr and the firebox and chimney are intact and made of masonry (noncombustible).
Step-by-step compliance check:
- Product listing: Confirm the appliance bears the ANSI Z21.60/CSA 2.26 listing — required by § 911.1. If the label and listing paperwork are present, this box is checked.
- Fireplace condition: Verify the chimney has a working flue and the firebox is constructed of noncombustible materials — required by § 911.3. If the chimney is functional and masonry, this is compliant.
- Location: The living room is not a bedroom, bathroom, hospital, skilled nursing facility, intermediate care facility, or correctional treatment center — so § 911.2 prohibitions do not preclude installation here.
- Controls: Do not connect the appliance to a thermostat or any automatic temperature control — § 911.3 forbids thermostatic control.
- Installation: Install the appliance in accordance with its listing and the manufacturer’s instructions — § 911.3.1. Keep the listing and instructions on file for inspectors.
Result: With the listed appliance, a working masonry flue, installation per manufacturer instructions, and no thermostatic control, the installation meets the CMC requirements found in § 911.1 and § 911.3, and is not barred by § 911.2.
(If the same appliance were proposed for a bedroom or bathroom, you must check § 701.4 to confirm the room’s required volume before proceeding; that numeric threshold was not included in the retrieved text here.)
Related provisions
- § 911.4 — Fireplace screens and accessories (related to decorative appliances for vented fireplaces).
- § 701.4 — Required room volume referenced by § 911.2 (verify numeric volume thresholds in this section).
- § 912.3 — Installation requirements for vented gas fireplaces (other gas-fireplace rules and listings).
- § 1312.6 — Appliance shutoff valve exceptions and locations (addresses shutoff valves for decorative appliances in fireplaces).
Code references
Grounded in the retrieved California Mechanical Code — click a citation to read the verbatim passage:
CMC § 907.2.3 High relevance — show source text
907.2.3 Panels, Grilles, and Access Doors. Panels, grilles, and access doors that are required to be removed for normal servicing operations shall not be attached to the building. For additional information on the venting of wall furnaces, see Section 802.0. [NFPA 54:10.25.2.4]
For SI units: 1 inch = 25.4 mm
FIGURE 907.2.1
INSTALLATION OF TYPE B-W GAS VENTS FOR
VENTED WALL FURNACES
[NFPA 54: FIGURE 10.25.2.2]
907.3 Location. Wall furnaces shall be located so as not to cause a hazard to walls, floors, curtains, furniture, or doors. Wall furnaces installed between bathrooms and adjoining rooms shall not circulate air from bathrooms to other parts of the building. [NFPA 54:10.25.3]
2025 CALIFORNIA MECHANICAL CODE 205
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
INSTALLATION OF SPECIFIC APPLIANCES
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910.0 Burner Assemblies.
910.1 Oil Burners. Oil burners shall comply with UL 296 and installed in accordance with the manufacturer’s installa tion instructions.
910.2 Gas Burners. Commercial gas burners shall comply with UL 295 and installed in accordance with the manufac turer’s installation instructions.
911.0 Decorative Appliances for Installation in Vented Fireplaces.
911.1 Application. Decorative appliances for installation in vented fireplaces shall be listed in accordance with ANSI Z21.60/CSA 2.26. [NFPA 54:10.6.1]
911.2 Prohibited Installations. Decorative appliances for installation in vented fireplaces shall not be installed in bathrooms or bedrooms unless the bedroom or bathroom has the
required volume in accordance with Section 701.4. [NFPA 54:10.6.2] [OSHPD 1, 1R, 2, 4 & 5] A vented decorative appliance shall not be located in any hospital, skilled nursing facility, intermediate care facility, or correctional treatment
center.
911.3 Installation. A decorative appliance for installation in a vented fireplace shall be installed only in a vented fireplace having a working chimney flue and constructed of noncombustible materials. These appliances shall not be thermostatically controlled. [NFPA 54:10.6.3]
911.3.1 Listed Decorative Appliance. A listed decorative appliance for installation in a vented fireplace shall be installed in accordance with its listing and the manufacturer’s installation instructions. {NFPA 54:10.6.3.1}
911.3.2 Reserved
911.4 Fireplace Screens. A fireplace screen shall be installed with a decorative appliance for installation in a vented fireplace. [NFPA 54:10.6.4]
912.0 Gas Fireplaces, Vented.
912.1 Application. Vented gas fireplaces shall be listed in accordance with ANSI Z21.50/CSA 2.22. [NFPA 54:10.7.1]
CMC § 911.2 High relevance — show source text
911.2 Prohibited Installations. Decorative appliances for installation in vented fireplaces shall not be installed in bathrooms or bedrooms unless the bedroom or bathroom has the
required volume in accordance with Section 701.4. [NFPA 54:10.6.2] [OSHPD 1, 1R, 2, 4 & 5] A vented decorative appliance shall not be located in any hospital, skilled nursing facility, intermediate care facility, or correctional treatment
center.
911.3 Installation. A decorative appliance for installation in a vented fireplace shall be installed only in a vented fireplace having a working chimney flue and constructed of noncombustible materials. These appliances shall not be thermostatically controlled. [NFPA 54:10.6.3]
911.3.1 Listed Decorative Appliance. A listed decorative appliance for installation in a vented fireplace shall be installed in accordance with its listing and the manufacturer’s installation instructions. {NFPA 54:10.6.3.1}
911.3.2 Reserved
911.4 Fireplace Screens. A fireplace screen shall be installed with a decorative appliance for installation in a vented fireplace. [NFPA 54:10.6.4]
912.0 Gas Fireplaces, Vented.
912.1 Application. Vented gas fireplaces shall be listed in accordance with ANSI Z21.50/CSA 2.22. [NFPA 54:10.7.1]
912.2 Reserved
912.3 Installation. The installation of vented gas fireplaces shall comply with the following requirements:
(1) [HCD 1 & HCD 2] Any newly installed gas fireplace shall be a direct-vent sealed-combustion type.
(2) Vented gas fireplaces shall be installed in accordance with their listing and the manufacturer’s installation instructions and where installed in or attached to com bustible material shall be specifically listed for such installation.
(3) Panels, grilles, and access doors that are required to be removed for normal servicing operations shall not be attached to the building.
(4) Direct vent gas fireplaces shall be installed with the vent air intake terminal in the outdoors and in accor dance with the manufacturer’s installation instructions.
[NFPA 54:10.7.3] 912.4 Combustion and Circulating Air. Combustion and circulating air shall be provided in accordance with Section 701.0. [NFPA 54:10.7.4]
913.0 Factory-Built Fireplaces and Fireplace Stoves. 913.1 Factory-Built Fireplaces. Factory-built fireplaces shall comply with UL 127 and installed in accordance with the manufacturer’s installation instructions. {NFPA 211:11.1.1} 913.1.1 Gasketed Fireplace Doors. A gasketed fireplace door shall not be installed on a factory-built fireplace, except where the fireplace system has been tested in accordance with UL 127.
913.2 Fireplace Stoves. Fireplace stoves shall comply with UL 737 and installed in accordance with the manufac turer’s installation instructions.
913.3 Fireplace Accessories. Heat exchangers, glass doors assemblies, combustion air vents, and termination caps shall comply with UL 907 and installed in accordance with the manufacturer’s installation instructions.
CMC § 907.0 High relevance — show source text
TABLE OF CONTENTS
907.0 Wall Furnaces. . . . . . . . . . . . . . . . 204
907.1 Application . . . . . . . . . . . . . . . . . . 204
907.2 Installation . . . . . . . . . . . . . . . . . . 204
907.3 Location . . . . . . . . . . . . . . . . . . . . 205
907.4 Combustion and Circulating Air . . 205
907.5 Oil-Fired Wall Furnaces . . . . . . . . 205
908.0 Clothes Dryers . . . . . . . . . . . . . . . 205
908.1 Application . . . . . . . . . . . . . . . . . . 205
908.2 Electric Clothes Dryers . . . . . . . . . 205
908.3 Gas-Fired Clothes Dryers. . . . . . . 205
909.0 Conversion Burners . . . . . . . . . . . 205
909.1 General. . . . . . . . . . . . . . . . . . . . . 205
910.0 Burner Assemblies . . . . . . . . . . . . 206
910.1 Oil Burners . . . . . . . . . . . . . . . . . . 206
910.2 Gas Burners . . . . . . . . . . . . . . . . . 206
911.0 Decorative Appliances for Installation in Vented Fireplaces. . . 206
911.1 Application . . . . . . . . . . . . . . . . . . 206
911.2 Prohibited Installations . . . . . . . . . 206
911.3 Installation . . . . . . . . . . . . . . . . . . 206
911.4 Fireplace Screens. . . . . . . . . . . . . 206
912.0 Gas Fireplaces, Vented . . . . . . . . 206
912.1 Application . . . . . . . . . . . . . . . . . . 206
912.2 Reserved . . . . . . . . . . . . . . . . . . . 206
912.3 Installation . . . . . . . . . . . . . . . . . . 206
912.4 Combustion and Circulating Air . . . 206
913.0 Factory-Built Fireplaces and Fireplace Stoves. . . . . . . . . . . . . . 206
913.1 Factory-Built Fireplaces . . . . . . . . 206
913.2 Fireplace Stoves. . . . . . . . . . . . . . 206
913.3 Fireplace Accessories . . . . . . . . . 206
914.0 Non-Recirculating Direct Gas-Fired Industrial Air Heaters. . . 206
914.1 Application . . . . . . . . . . . . . . . . . . 206
914.2 Prohibited Installations . . . . . . . . . 206
914.3 Installation . . . . . . . . . . . . . . . . . . 206
914.4 Clearance from Combustible
Materials . . . . . . . . . . . . . . . . . . . . 207
California Mechanical Code High relevance — show source text
5
8|NA
NA
NA|NA
NA
NA|265
246
237|NA
NA
NA|NA
NA
NA|349
327
317|382
NA
NA|725
NA
NA|445
422
408|549
673
747|1021
1003
985|650
638
621| |10|2
5
10|216
NA
NA|518
NA
NA|297
276
261|271
334
NA|654
635
NA|387
364
345|373
459
547|808
789
758|490
465
441|536
657
771|1142
1121
1088|722
710
665| |15|2
5
10
15|211
261
NA
NA|611
591
NA
NA|335
312
294
278|264
325
392
452|776
755
722
692|440
414
392
372|362
444
531
606|965
942
907
873|560
531
504
481|520
637
749
841|1373
1348
1309
1272|840
825
774
738| |20|2
5
10
15
20|206
255
312
NA
NA|675
655
622
NA
NA|374
348
330
311
292|258
317
382
442
NA|864
842
806
773
NA|490
461
437
414
392|252
433
517
591
663|1079
1055
1016
979
944|625
594
562
539
510|508
623
733
823
911|1544
1518
1475
1434
1394|950
930
875
835
800| |30|2
5CMC § 905.8 High relevance — show source text
905.8 Installation in Commercial
Garages and Aircraft Hangars . . . 203
905.9 Electric Duct Heaters . . . . . . . . . . 203
906.0 Floor Furnaces . . . . . . . . . . . . . . . 203
906.1 Application . . . . . . . . . . . . . . . . . . 203
906.2 Installation . . . . . . . . . . . . . . . . . . 204
906.3 Temperature Limit Controls . . . . . 204
906.4 Combustion and Circulating Air. . . 204
906.5 Placement. . . . . . . . . . . . . . . . . . . 204
906.6 Bracing . . . . . . . . . . . . . . . . . . . . . 204
906.7 Support . . . . . . . . . . . . . . . . . . . . . 204
906.8 Clearance . . . . . . . . . . . . . . . . . . . 204
906.9 Access . . . . . . . . . . . . . . . . . . . . . 204
906.10 Seepage Pan . . . . . . . . . . . . . . . . 204
906.11 Wind Protection . . . . . . . . . . . . . . 204
906.12 Upper Floor Installations. . . . . . . . 204
906.13 First Floor Installation . . . . . . . . . . 204
906.14 Oil-Fired Floor Furnaces. . . . . . . . 204
xxxv
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
TABLE OF CONTENTS
907.0 Wall Furnaces. . . . . . . . . . . . . . . . 204
907.1 Application . . . . . . . . . . . . . . . . . . 204
907.2 Installation . . . . . . . . . . . . . . . . . . 204
907.3 Location . . . . . . . . . . . . . . . . . . . . 205
907.4 Combustion and Circulating Air . . 205
907.5 Oil-Fired Wall Furnaces . . . . . . . . 205
908.0 Clothes Dryers . . . . . . . . . . . . . . . 205
908.1 Application . . . . . . . . . . . . . . . . . . 205
908.2 Electric Clothes Dryers . . . . . . . . . 205
908.3 Gas-Fired Clothes Dryers. . . . . . . 205
909.0 Conversion Burners . . . . . . . . . . . 205
909.1 General. . . . . . . . . . . . . . . . . . . . . 205
910.0 Burner Assemblies . . . . . . . . . . . . 206
910.1 Oil Burners . . . . . . . . . . . . . . . . . . 206
910.2 Gas Burners . . . . . . . . . . . . . . . . . 206
911.0 Decorative Appliances for Installation in Vented Fireplaces. . . 206
California Mechanical Code High relevance — show source text
INPUT RATING LIMITS IN THOUSANDS OF BTU PER HOUR**| |VENT
HEIGHT
_H _
(feet)|CONNECTOR
RISE
_R _
(feet)|FAN|FAN|NAT|FAN|FAN|NAT|FAN|FAN|NAT| |VENT
HEIGHT
_H _
(feet)|CONNECTOR
RISE
_R _
(feet)|Min|Max|Max|Min|Max|Max|Min|Max|Max| |6|2
4
6|NA
NA
NA|NA
NA
NA|NA
NA
NA|NA
NA
NA|NA
NA
NA|NA
NA
NA|NA
NA
NA|NA
NA
NA|NA
NA
NA| |8|2
4
6|NA
471
478|NA
2737
3018|NA
1800
2180|NA
560
568|NA
3319
3665|NA
2180
2640|NA
662
669|NA
3957
4373|NA
2590
3130| |10|2
4
6|NA
486
494|NA
2887
3169|NA
1890
2290|NA
581
589|NA
3502
3849|NA
2280
2760|NA
686
694|NA
4175
4593|NA
2710
3270| |15|2
4
6|NA
523
533|NA
3197
3470|NA
2060
2510|NA
624
634|NA
3881
4216|NA
2490
3030|NA
734
743|NA
4631
5035|NA
2960
3600| |20|2
4
6|NA
554
567|NA
3447
3708|NA
2180
2650|NA
661
671|NA
4190
4511|NA
2630
3190|NA
772
785|NA
5005
5392|NA
3130
3790| |30|2
4
6|NA
619
632|NA
3840
4080|NA
2365
2875|NA
728
741|NA
4861
4976|NA
2860
3480|NA
847
860|NA
5606
5961|NA
3410
4150| |50|2
4California Mechanical Code High relevance — show source text
5|NA
NA|NA
NA|28
25|NA
NA|NA
NA|52
49|NA
NA|NA
NA|86
82|NA
NA|NA
NA|130
117|NA
NA|NA
NA|180
165| |8|2
5
8|NA
NA
NA|NA
NA
NA|29
26
24|NA
NA
NA|NA
NA
NA|55
52
48|NA
NA
NA|NA
NA
NA|93
88
83|NA
NA
NA|NA
NA
NA|145
134
127|NA
NA
NA|NA
NA
NA|198
183
175| |10|2
5
10|NA
NA
NA|NA
NA
NA|31
28
25|NA
NA
NA|NA
NA
NA|61
57
50|NA
NA
NA|NA
NA
NA|103
96
87|NA
NA
NA|NA
NA
NA|162
148
139|NA
NA
NA|NA
NA
NA|221
204
191| |15|2
5
10
15|NA
NA
NA
NA|NA
NA
NA
NA|35
35
28
NA|NA
NA
NA
NA|NA
NA
NA
NA|67
62
55
48|NA
NA
NA
NA|NA
NA
NA
NA|114
107
97
89|NA
NA
NA
NA|NA
NA
NA
NA|179
164
153
141|53
NA
NA
NA|475
NA
NA
NA|250
231
216
201| |20|2
5
10
15
20|NA
NA
NA
NA
NA|NA
NA
NA
NA
NA|38
36
NA
NA
NA|NA
NA
NA
NA
NA|NA
NA
NA
NA
NA|74
68
60
NA
NA|NA
NA
NA
NA
NA|NA
NA
NA
NA
NA|124
116
107
97
83|NA
NA
NA
NA
NA|NA
NA
NA
NA
NA|201
184
172
159
148|51
80
NA
NA
NA|522
503
NA
NA
NA|274
254
237
220
206| |30|2
5CMC § 110.5 Medium relevance — show source text
(f) Installation of fireplaces, decorative gas appliances and gas logs. If a masonry or factory-built fireplace is installed, it shall comply with Section 110.5, Section 4.503 of Part 11, and shall have the following:
- Closable metal or glass doors covering the entire opening of the firebox; and
- A combustion air intake to draw air from the outside of the building, which is at least 6 square inches in area and is equipped with a readily accessible, operable and tight-fitting damper or combustion-air control device; and Exception to Section 160.1(f)2: An outside combustion-air intake is not required if the fireplace will be installed over concrete slab flooring and the fireplace will not be located on an exterior wall.
- A flue damper with a readily accessible control. Exception to Section 160.1(f)3: When a gas log, log lighter or decorative gas appliance is installed in a fireplace, the flue damper shall be blocked open if required by the CMC or the manufacturer's installation instructions.
(g) Slab edge insulation. Slab edge insulation shall meet the following minimum specifications:
Insulation material alone without the facing shall have a water absorption rate no greater than 0.3 percent when tested in accordance with ASTM C272, Test Method A – 24-Hour-Immersion; and
Water vapor permeance no greater than 2.0 perm/inch when tested in accordance with ASTM C272; and
Concrete slab perimeter insulation shall be protected from physical damage and ultraviolet light deterioration; and
Insulation for a heated slab floor shall meet the requirements of Section 110.8(g).
NOTE: Authority: Sections 25213, 25218, 25218.5, 25402 and 25402.1, Public Resources Code . Reference: Sections 25007, 25008, 25218.5, 25310, 25402, 25402.1, 25402.4, 25402.5, 25402.8 and 25943, Public Resources Code .
SECTION 160.2—MANDATORY REQUIREMENTS FOR VENTILATION AND INDOOR AIR QUALITY
(a) General requirements.
- Attached dwelling units in multifamily buildings shall comply with the applicable requirements of Subsection 160.2(b) below. Occupiable spaces in multifamily buildings other than attached dwelling units shall comply with the applicable requirements of Section 160.2(c). When field verification and diagnostic testing of attached dwelling units is required by Section 160.2, buildings with three habitable stories or fewer shall use the applicable procedures in the Residential Appendices, and buildings with four or more habitable stories shall use the applicable procedures in Nonresidential Appendices NA1 and NA2.
NOTE: Section 160.2 is not applicable to townhouses or dwellings that contain two dwelling units.
200 2025 CALIFORNIA ENERGY CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
MULTIFAMILY BUILDINGS—MANDATORY REQUIREMENTS
- The required outdoor air-ventilation rate and the air-distribution system design shall be clearly identified on the building design plans submitted to the enforcement agency in accordance with Section 10-103 of Title 24, Part 1.
(b) Attached dwelling units. Attached dwelling units shall comply with the requirements of Subsections 1 and 2 below.
- Air filtration.
California Mechanical Code Medium relevance — show source text
5
10|NA
NA
NA|NA
NA
NA|31
28
25|NA
NA
NA|NA
NA
NA|61
57
50|NA
NA
NA|NA
NA
NA|103
96
87|NA
NA
NA|NA
NA
NA|162
148
139|NA
NA
NA|NA
NA
NA|221
204
191| |15|2
5
10
15|NA
NA
NA
NA|NA
NA
NA
NA|35
35
28
NA|NA
NA
NA
NA|NA
NA
NA
NA|67
62
55
48|NA
NA
NA
NA|NA
NA
NA
NA|114
107
97
89|NA
NA
NA
NA|NA
NA
NA
NA|179
164
153
141|53
NA
NA
NA|475
NA
NA
NA|250
231
216
201| |20|2
5
10
15
20|NA
NA
NA
NA
NA|NA
NA
NA
NA
NA|38
36
NA
NA
NA|NA
NA
NA
NA
NA|NA
NA
NA
NA
NA|74
68
60
NA
NA|NA
NA
NA
NA
NA|NA
NA
NA
NA
NA|124
116
107
97
83|NA
NA
NA
NA
NA|NA
NA
NA
NA
NA|201
184
172
159
148|51
80
NA
NA
NA|522
503
NA
NA
NA|274
254
237
220
206| |30|2
5CMC § 0.037. Medium relevance — show source text
In wood framed assemblies, compliance with U -factors may be demonstrated by installing wall insulation with an R -value of R-15 in 2x4 assemblies, and R-21 in 2x6 assemblies with 16 inches on center spacing.
(d) Raised-floor insulation. Raised floors separating conditioned space from unconditioned space or ambient air shall have an overall assembly U -factor not exceeding U-0.037. In a wood framed assembly, compliance with the U -factor may be demonstrated by installing insulation with an R -value of 19 or greater.
Exception to Section 150.0(d): A building with a controlled ventilation or unvented crawlspace may omit raised floor insulation if all of the following are met: i. The foundation walls are insulated to meet the wall insulation minimums as shown in Table 150.1-A; and
ii. A Class I or Class II vapor retarder is placed over the entire floor of the crawl space; and iii. Vents between the crawlspace and outside air are fitted with automatically operated louvers that are temperature actuated; and
2025 CALIFORNIA ENERGY CODE 159
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
SINGLE-FAMILY RESIDENTIAL BUILDINGS— MANDATORY FEATURES AND DEVICES
iv. The requirements in Reference Residential Appendix RA4.5.1.
(e) Installation of fireplaces, decorative gas appliances and gas logs. If a masonry or factory-built fireplace is installed, it shall comply with Section 110.5, Section 4.503 of Part 11, and shall have the following:
- Closable metal or glass doors covering the entire opening of the firebox; and
- A combustion air intake to draw air from the outside of the building, which is at least 6 square inches in area and is equipped with a readily accessible, operable and tight-fitting damper or combustion-air control device; and Exception to Section 150.0(e)2: An outside combustion-air intake is not required if the fireplace will be installed over concrete slab flooring and the fireplace will not be located on an exterior wall.
- A flue damper with a readily accessible control. Exception to Section 150.0(e)3: When a gas log, log lighter or decorative gas appliance is installed in a fireplace, the flue damper shall be blocked open if required by the CMC or the manufacturer’s installation instructions.
(f) Slab edge insulation. Material used for slab edge insulation shall meet the following minimum specifications:
Water absorption rate for the insulation material alone without facings no greater than 0.3 percent when tested in accordance with Test Method A – 24-Hour-Immersion of ASTM C272.
Water vapor permeance no greater than 2.0 perm/inch when tested in accordance with ASTM E96.
Concrete slab perimeter insulation shall be protected from physical damage and ultraviolet light deterioration.
Insulation for a heated slab floor shall meet the requirements of Section 110.8(g).
(g) Vapor retarder.
- In Climate Zones 1–16, the earth floor of unvented crawl space shall be covered with a Class I or Class II vapor retarder. This requirement shall also apply to controlled ventilation crawl space for buildings complying with the Exception to Section 150.0(d).
CMC § 10.4.2 Medium relevance — show source text
(3) Unlisted clothes dryers shall be installed with clearances to combustible material of not less than 18
inches (457 mm). Combustible floors under unlisted clothes dryers shall be protected in an approved manner. {NFPA 54:10.4.2}
908.3.2 Exhausting to the Outdoors. Type 1 and Type 2 clothes dryers shall be exhausted to the outside air in accordance with Section 504.4. {NFPA 54:10.4.3}
908.3.3 Multiple-Family or Public Use. All clothes dryers installed for multiple-family or public use shall be installed as specified for a Type 2 clothes dryer under Section 504.4.3.1. [NFPA 54:10.4.7]
909.0 Conversion Burners.
909.1 General. Installation of conversion burners shall con form to CSA Z21.8. [NFPA 54:10.5]
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shall be permitted to be an integral part of the vented wall furnace, as illustrated in Figure 907.2.1. The stud space in which the vented wall furnace is installed shall be ventilated at the first ceiling level by installation of the ceiling plate spacers furnished with the gas vent. Firestop spacers shall be installed at each subsequent ceiling or floor level penetrated by the vent. [NFPA 54:10.25.2.2]
907.2.2 Direct Vent Wall Furnaces. Direct vent wall
furnaces shall be installed with the combustion air intake
terminal outdoors. [NFPA 54:10.25.2.3]
907.2.3 Panels, Grilles, and Access Doors. Panels, grilles, and access doors that are required to be removed for normal servicing operations shall not be attached to the building. For additional information on the venting of wall furnaces, see Section 802.0. [NFPA 54:10.25.2.4]
For SI units: 1 inch = 25.4 mm
FIGURE 907.2.1
INSTALLATION OF TYPE B-W GAS VENTS FOR
VENTED WALL FURNACES
[NFPA 54: FIGURE 10.25.2.2]
907.3 Location. Wall furnaces shall be located so as not to cause a hazard to walls, floors, curtains, furniture, or doors. Wall furnaces installed between bathrooms and adjoining rooms shall not circulate air from bathrooms to other parts of the building. [NFPA 54:10.25.3]
2025 CALIFORNIA MECHANICAL CODE 205
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
INSTALLATION OF SPECIFIC APPLIANCES
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910.0 Burner Assemblies.
910.1 Oil Burners. Oil burners shall comply with UL 296 and installed in accordance with the manufacturer’s installa tion instructions.
910.2 Gas Burners. Commercial gas burners shall comply with UL 295 and installed in accordance with the manufac turer’s installation instructions.
911.0 Decorative Appliances for Installation in Vented Fireplaces.
Frequently asked questions
Can I install a decorative gas log in a bedroom?
Only if the bedroom meets the required volume in § 701.4. § 911.2 prohibits installation in bedrooms unless that volume requirement is met; check § 701.4 for the numeric threshold.
Does the appliance have to be listed?
Yes — appliances for installation in vented fireplaces must be listed in accordance with ANSI Z21.60/CSA 2.26 per § 911.1.
Can I add a thermostat to control a decorative fireplace appliance?
No. § 911.3 expressly states these appliances shall not be thermostatically controlled.
Are decorative appliances allowed in hospitals or nursing homes?
No. § 911.2 states a vented decorative appliance shall not be located in hospitals, skilled nursing facilities, intermediate care facilities, or correctional treatment centers.
Must I follow the manufacturer’s installation instructions?
Yes. A listed decorative appliance must be installed in accordance with its listing and the manufacturer's instructions per § 911.3.1.
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