CHBC · California Historical Building Code

Mechanical systems

The CHBC’s mechanical provisions protect life safety while allowing preservation‑sensitive solutions for HVAC, combustion, venting, ducts and related equipment.

Last reviewed: July 6, 2026

Overview

This part of the California Historical Building Code (CHBC) governs heating, ventilation, air‑conditioning, fuel‑burning appliances, venting and ducts, and other heat‑producing equipment in qualified historical buildings. The CHBC applies these rules while allowing preservation‑sensitive solutions — see § 8-902 (Mechanical) for the mechanical provisions and § 8-901 (Purpose, intent and scope) for how the CHBC is applied in conjunction with the regular code .

The chapter emphasizes life‑safety and practical flexibility: existing systems that do not create a safety hazard may remain, and enforcing agencies may accept alternatives that achieve equivalent life safety. Specific topics addressed include combustion air and appliance venting, duct and ventilating systems, grease hood requirements, and miscellaneous equipment rules (see § 8-902.1–8-902.9) .

In this section

Code references

Grounded in the retrieved California Historical Building Code — click a citation to read the verbatim passage:

  • CHBC § 8-901.5 High relevance — show source text

    8-901.5 Energy conservation. Qualified historical buildings or properties covered by this part are exempted from compliance with energy conservation standards. When new nonhistorical lighting and space conditioning system components, devices, appliances and equipment are installed, they shall comply with the requirements of Title 24, Part 6, The California Energy Code, except where the historical significance or character-defining features are threatened.

    SECTION 8-902 MECHANICAL

    8-902.1 General. Mechanical systems shall comply with the regular code unless otherwise modified by this chapter.

    8-902.1.1 The provisions of the CHBC shall apply to the acceptance, location, installation, alteration, repair, relocation, replacement or addition of any heating, ventilating, air conditioning, domestic incinerators, kilns or miscellaneous heat-producing appliances or equipment within or attached to a historical building.

    8-902.1.2 Existing systems which do not, in the opinion of the enforcing agency, constitute a safety hazard may remain in use.

    8-902.1.3 The enforcing agency may approve any alternative to the CHBC which would achieve equivalent life safety.

    8-902.2 Heating facilities. All dwelling-type occupancies covered under this chapter shall be provided with heating facilities. Woodburning or pellet stoves or fireplaces may be acceptable as heating facilities.

    8-902.3 Fuel oil piping and tanks. Fuel oil piping and tanks shall comply with regular code requirements except that the enforcing agency may waive such requirements where the lack of compliance does not create a safety or environmental hazard.

    8-902.4 Heat-producing and cooling equipment. Heat-producing and cooling equipment shall comply with the regular code requirements governing equipment safety, except that the enforcing agency may accept alternatives which do not create a safety hazard.

    8-902.5 Combustion air.

    8-902.5.1 All fuel-burning appliances and equipment shall be provided a sufficient supply of air for proper fuel combustion, ventilation and draft hood dilution.

    8-902.5.2 The enforcing agency may require operational tests for combustion air systems which do not comply with applicable requirements of the regular code.

    8-902.6 Venting of appliances.

    8-902.6.1 Every appliance required to be vented shall be connected to an approved venting system. Venting systems shall develop a positive flow adequate to convey all combustion products to the outside atmosphere.

    8-902.6.2 Masonry chimneys in structurally sound condition may remain in use for all fuel-burning appliances, provided the flue is evaluated and documentation provided that the masonry and grout are in good condition. Terra cotta chimneys and Type C metallic vents installed in concealed spaces shall not remain in use unless otherwise mitigated and approved on a case-by-case basis.

    8-902.6.3 The enforcing agency may require operational tests for venting systems which do not comply with applicable requirements of the regular code.

    8-902.7 Ducts.

    8-902.7.1 New ducts shall be constructed and installed in accordance with applicable requirements of the regular code.

    8-902.7.2 Existing duct systems which do not comply with applicable requirements of the regular code and do not, in the opinion of the enforcing agency, constitute a safety or health hazard may remain in use.

    8-902.8 Ventilating systems.

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  • CHBC § 8-9 High relevance — show source text

    Bolt spacing shall not
    exceed 6 feet (1830 mm) on center and shall not be less than 12 inches (305 mm) on center.
    6. Other masonry based on tests or other substantiated data.
    7. Embedded bolts to be tested as specified in regular code standards.
    8. Stresses given may be increased for combinations of loads as specified in the regular code.
    9. Adhesives shall be approved by the enforcing agency and installed in accordance with the manufacturer’s recommendations. All drilling dust shall be removed from drilled
    holes prior to installation.|

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    8-9 MECHANICAL, PLUMBING AND ELECTRICAL REQUIREMENTS

    SECTION 8-901 PURPOSE, INTENT AND SCOPE

    8-901.1 Purpose. The purpose of the CHBC is to provide regulations for the mechanical, plumbing and electrical systems of buildings designated as qualified historical buildings or properties. The CHBC requires enforcing agencies to accept any reasonable equivalent solutions to the regular code when dealing with qualified historical buildings or properties.

    8-901.2 Intent. The intent of the CHBC is to preserve the integrity of qualified historical buildings or properties while providing a reasonable level of protection from fire, health and life safety hazards (hereinafter referred to as safety hazards) for the building occupants.

    8-901.3 Scope. The CHBC shall be applied in conjunction with the regular code whenever compliance with the regular code is required for qualified historical buildings or properties.

    8-901.4 Safety hazard. No person shall permit any safety hazard to exist on premises under their control, or fail to take immediate action to abate such hazard. Existing systems which constitute a safety hazard when operational may remain in place, provided they are completely and permanently rendered inoperative. Safety hazards created by inoperative systems shall not be permitted to exist. Requirements of the regular code concerning general regulations shall be complied with, except that the enforcing agency shall accept solutions which do not cause a safety hazard.

    8-901.5 Energy conservation. Qualified historical buildings or properties covered by this part are exempted from compliance with energy conservation standards. When new nonhistorical lighting and space conditioning system components, devices, appliances and equipment are installed, they shall comply with the requirements of Title 24, Part 6, The California Energy Code, except where the historical significance or character-defining features are threatened.

    SECTION 8-902 MECHANICAL

    8-902.1 General. Mechanical systems shall comply with the regular code unless otherwise modified by this chapter.

    8-902.1.1 The provisions of the CHBC shall apply to the acceptance, location, installation, alteration, repair, relocation, replacement or addition of any heating, ventilating, air conditioning, domestic incinerators, kilns or miscellaneous heat-producing appliances or equipment within or attached to a historical building.

    8-902.1.2 Existing systems which do not, in the opinion of the enforcing agency, constitute a safety hazard may remain in use.

    8-902.1.3 The enforcing agency may approve any alternative to the CHBC which would achieve equivalent life safety.

    8-902.2 Heating facilities. All dwelling-type occupancies covered under this chapter shall be provided with heating facilities. Woodburning or pellet stoves or fireplaces may be acceptable as heating facilities.

  • CHBC § 2.25 High relevance — show source text

    00|2.25|0.70|DR|3.70|1.05|DR|DR| |Minimum 33
    mil steel
    furring or
    minimum
    1x wood
    furringc|33 mil cold-
    formed steel
    stud|#10 screw|Steel thick-
    ness plus 3
    threads|16|3.85|1.45|DR|DR|3.40|DR|DR|DR| |Minimum 33
    mil steel
    furring or
    minimum
    1x wood
    furringc|33 mil cold-
    formed steel
    stud|#10 screw|Steel thick-
    ness plus 3
    threads|24|3.40|DR|DR|DR|2.70|DR|DR|DR| |Minimum 33
    mil steel
    furring or
    minimum
    1x wood
    furringc|43 mil or
    thicker cold-
    formed steel
    stud|#8 Screw|Steel thick-
    ness plus 3
    threads|12|3.00|1.80|DR|DR|3.00|0.65|DR|DR| |Minimum 33
    mil steel
    furring or
    minimum
    1x wood
    furringc|43 mil or
    thicker cold-
    formed steel
    stud|#8 Screw|Steel thick-
    ness plus 3
    threads|16|3.00|1.00|DR|DR|2.85|DR|DR|DR| |Minimum 33
    mil steel
    furring or
    minimum
    1x wood
    furringc|43 mil or
    thicker cold-
    formed steel
    stud|#8 Screw|Steel thick-
    ness plus 3
    threads|24|2.85|DR|DR|DR|2.20|DR|DR|DR| |Minimum 33
    mil steel
    furring or
    minimum
    1x wood
    furringc|43 mil or
    thicker cold-
    formed steel
    stud|#10 screw|Steel thick-
    ness plus 3
    threads|12|4.00|3.85|2.80|1.80|4.00|3.05|1.50|DR| |Minimum 33
    mil steel
    furring or
    minimum
    1x wood
    furringc|43 mil or
    thicker cold-
    formed steel
    stud|#10 screw|Steel thick-
    ness plus 3
    threads|16|4.00|3.30|1.95|0.60|4.00|2.25|DR|DR| |Minimum 33
    mil steel
    furring or
    minimum
    1x wood
    furringc|43 mil or
    thicker cold-
    formed steel
    stud|#10 screw|Steel thick-
    ness plus 3
    threads|24|4.00|2.25|DR|DR|4.00|0.65|DR|DR| |For SI: 1 inch = 25.4 mm, 1 pound per square foot (psf) = 0.0479 kPa, 1 pound per square inch = 0.00689 MPa.
    DR = Design Required, o.c. = on center.
    a. Wood furring shall be spruce-pine-fir or any softwood species with a specific gravity of 0.42 or greater.

  • CHBC § 1106.2.6. High relevance — show source text

    (1) The space(s) containing the machinery is (are) separated from other occupancies by tight construction with tightfitting doors.

    (2) Access is restricted to authorized personnel.

    (3) Refrigerant detectors are installed with the sensing location and alarm level as required in refrigeration machinery rooms in accordance with Section 1106.2.6.

    (4) Open flames and surfaces exceeding 800°F (427°C) shall not be permitted where a Group A2, B2, A3, or B3 refrigerant, is used.

    (5) Electrical equipment that is in accordance with Class 1, Division 2, of NFPA 70 where the quantity of a Group A2, B2, A3, or B3 refrigerant in an independent circuit is capable of exceeding 25 percent of the lower flammability limit (LFL) upon release to the space based on the volume determined in accordance with Section 1104.2.1 through Section 1104.2.3.

    (6) Refrigerant containing parts in systems exceeding 100 horsepower (74.6 kW) compressor drive power, except evaporators used for refrigeration or dehumidification, condensers used for heating, control and pressure-relief valves for either, low-probability pumps, and connecting piping, are located in a machinery room or outdoors.

    [ASHRAE 15:7.2.2]

    1104.5 Flammable Refrigerants. The total of Group A2, B2, A3, and B3 refrigerants, other than Group A2L and B2L refrigerants shall not exceed 1100 pounds (498.9 kg) without approval by the Authority Having Jurisdiction. Institutional Occupancies shall comply with Section 1104.3. Machinery rooms required in accordance with Section 1106.0 based on flammability shall be constructed and maintained in accordance with Section 1106.2.1 through Section 1106.2.6 and Section 1106.11 for Group A2L and B2L refrigerants. 1104.6 Group A2L Refrigerants for Human Comfort. High-probability systems using Group A2L refrigerants for human comfort applications shall comply with this section.

    [ASHRAE 15:7.6]

    1104.6.1 Refrigerant Concentration Limits. Occupied spaces shall comply with the releasable charge limitations of the equipment listing and ASHRAE 15. Unoccupied spaces with refrigerant containing equipment, not including continuous piping or tubing, shall comply with the releasable charge limitations of the equipment listing or Section 1104.6.4. {ASHRAE 15:7.6.1-7.6.1.2}

    1104.6.2 Listing and Installation Requirements. Refrigeration systems shall be listed and shall be installed in accordance with listing, the manufacturer’s instructions, and any markings on the equipment restricting the installation. [ASHRAE 15:7.6.2]

    1104.6.2.1 Nameplate. The nameplate required by Section 1115.5 shall include a symbol indicating that a flammable refrigerant is used, as specified by the product listing. [ASHRAE 15:7.6.2.1]

    1104.6.2.2 Labeling. A label indicating a flammable refrigerant is used shall be placed adjacent to service ports and other locations where service involving components containing refrigerant is performed, as specified by the product listing.

  • CHBC § 12.7 High relevance — show source text

    Values are for strength level loads as defined in regular code standards.
    2. Values may be adjusted for other fasteners when approved by the enforcing authority.
    3. In addition to existing sheathing value.
    4. Bolts to be1/2-inch (12.7 mm) minimum diameter.
    5. Other bolt sizes, values and installation methods may be used provided a testing program is conducted in accordance with regular code standards. Bolt spacing shall not
    exceed 6 feet (1830 mm) on center and shall not be less than 12 inches (305 mm) on center.
    6. Other masonry based on tests or other substantiated data.
    7. Embedded bolts to be tested as specified in regular code standards.
    8. Stresses given may be increased for combinations of loads as specified in the regular code.
    9. Adhesives shall be approved by the enforcing agency and installed in accordance with the manufacturer’s recommendations. All drilling dust shall be removed from drilled
    holes prior to installation.|1. Values are for strength level loads as defined in regular code standards.
    2. Values may be adjusted for other fasteners when approved by the enforcing authority.
    3. In addition to existing sheathing value.
    4. Bolts to be1/2-inch (12.7 mm) minimum diameter.
    5. Other bolt sizes, values and installation methods may be used provided a testing program is conducted in accordance with regular code standards. Bolt spacing shall not
    exceed 6 feet (1830 mm) on center and shall not be less than 12 inches (305 mm) on center.
    6. Other masonry based on tests or other substantiated data.
    7. Embedded bolts to be tested as specified in regular code standards.
    8. Stresses given may be increased for combinations of loads as specified in the regular code.
    9. Adhesives shall be approved by the enforcing agency and installed in accordance with the manufacturer’s recommendations. All drilling dust shall be removed from drilled
    holes prior to installation.|

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    8-9 MECHANICAL, PLUMBING AND ELECTRICAL REQUIREMENTS

    SECTION 8-901 PURPOSE, INTENT AND SCOPE

    8-901.1 Purpose. The purpose of the CHBC is to provide regulations for the mechanical, plumbing and electrical systems of buildings designated as qualified historical buildings or properties. The CHBC requires enforcing agencies to accept any reasonable equivalent solutions to the regular code when dealing with qualified historical buildings or properties.

    8-901.2 Intent. The intent of the CHBC is to preserve the integrity of qualified historical buildings or properties while providing a reasonable level of protection from fire, health and life safety hazards (hereinafter referred to as safety hazards) for the building occupants.

    8-901.3 Scope. The CHBC shall be applied in conjunction with the regular code whenever compliance with the regular code is required for qualified historical buildings or properties.

  • CHBC § 8-902.5 Medium relevance — show source text

    8-902.5 Combustion air.

    8-902.5.1 All fuel-burning appliances and equipment shall be provided a sufficient supply of air for proper fuel combustion, ventilation and draft hood dilution.

    8-902.5.2 The enforcing agency may require operational tests for combustion air systems which do not comply with applicable requirements of the regular code.

    8-902.6 Venting of appliances.

    8-902.6.1 Every appliance required to be vented shall be connected to an approved venting system. Venting systems shall develop a positive flow adequate to convey all combustion products to the outside atmosphere.

    8-902.6.2 Masonry chimneys in structurally sound condition may remain in use for all fuel-burning appliances, provided the flue is evaluated and documentation provided that the masonry and grout are in good condition. Terra cotta chimneys and Type C metallic vents installed in concealed spaces shall not remain in use unless otherwise mitigated and approved on a case-by-case basis.

    8-902.6.3 The enforcing agency may require operational tests for venting systems which do not comply with applicable requirements of the regular code.

    8-902.7 Ducts.

    8-902.7.1 New ducts shall be constructed and installed in accordance with applicable requirements of the regular code.

    8-902.7.2 Existing duct systems which do not comply with applicable requirements of the regular code and do not, in the opinion of the enforcing agency, constitute a safety or health hazard may remain in use.

    8-902.8 Ventilating systems.

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    MECHANICAL, PLUMBING AND ELECTRICAL REQUIREMENTS

    8-902.8.1 Ventilating systems shall be installed so that no safety hazard is created.

    8-902.8.2 Grease hoods and grease hood exhaust systems shall be furnished and installed in accordance with applicable requirements of the regular code. Existing systems which are altered shall comply with the regular code.

    8-902.9 Miscellaneous equipment requirements.

    8-902.9.1 The following appliances and equipment shall be installed so that no safety hazard is created: warm air furnaces, space heating equipment, vented decorative appliances, floor furnaces, vented wall furnaces, unit heaters, room heaters, absorption units, refrigeration equipment, duct furnaces, infrared radiant heaters, domestic incinerators, miscellaneous heat-producing appliances and water heaters.

    8-902.9.2 Storage-type water heaters shall be equipped with a temperature- and pressure-relief valve in accordance with applicable requirements of the regular code.

    SECTION 8-903 PLUMBING

    8-903.1 General. Plumbing systems shall comply with the regular code unless otherwise noted.

    8-903.1.1 The provisions of the CHBC shall apply to the acceptance, location, installation, alteration, repair, relocation, replacement or addition of any plumbing system or equipment within or attached to a historical building.

    8-903.1.2 Existing systems which do not, in the opinion of the enforcing agency, constitute a safety hazard may remain in use.

    8-903.1.3 The enforcing agency may approve any alternative to these regulations which achieves reasonably equivalent life safety.

    8-903.2 Residential occupancies.

  • CHBC § 8-705.1 Medium relevance — show source text

    8-705.1 Gravity loads. The capacity of the structure to resist gravity loads shall be evaluated and the structure strengthened as necessary. The evaluation shall include all parts of the load path. Where no distress is evident, and a complete load path is present, the structure may be assumed adequate by having withstood the test of time if anticipated dead and live loads will not exceed those historically present.

    8-705.2 Wind and seismic loads. The ability of the structure to resist wind and seismic loads shall be evaluated. Wind loads shall be considered when appropriate, but need not exceed 75 percent of the wind loads prescribed by the regular code. The evaluation shall be based on the requirements of Section 8-706.

    8.705.2.1 Any unsafe conditions in the lateral-load-resisting system shall be corrected, or alternative resistance shall be provided. When strengthening is required, additional resistance shall be provided to meet the minimum requirements of the CHBC. The strengthening measures shall be selected with the intent of meeting the performance objectives set forth in Section 8-701.2. The evaluation of structural members and structural systems for seismic loads shall consider the inelastic performance of structural members and their ability to maintain load-carrying capacity during the seismic loadings prescribed by the regular code.

    8.705.2.2 The architect or engineer shall consider additional measures with minimal loss of, and impact to, historical materials which will reduce damage and needed repairs in future earthquakes to better preserve the historical structure in perpetuity. These additional measures shall be presented to the owner for consideration as part of the rehabilitation or restoration.

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    STRUCTURAL REGULATIONS

    SECTION 8-706 LATERAL LOAD REGULATIONS

    8-706.1 Seismic forces. Strength-level seismic forces used to evaluate the structure for resistance to seismic loads shall be based on the R -values tabulated in the regular code for similar lateral-force-resisting systems including consideration of the structural detailing of the members where such R -values exist. Where such R -values do not exist, an appropriate R -value shall be rationally assigned considering the structural detailing of the members.

    Exceptions:

    1. The forces need not exceed 0.75 times the seismic forces prescribed by the regular code requirements.
    2. For Risk Category I, II or III structures, near-fault increases in ground motion (maximum considered earthquake ground motion of 0.2 second spectral response greater than 150 percent at 5 percent damping) need not be considered when the fundamental period of the building is 0.5 seconds in the direction under consideration.
    3. For Risk Category I or II structures, the seismic base shear need not exceed 0.30W.
    4. For Risk Category III or IV structures, the seismic base shear need not exceed 0.40W.

    8-706.1.1 When a building is to be strengthened with the addition of a new lateral force resisting system, the R -value of the new system can be used when the new lateral force resisting system resists at least 75 percent of the building’s base shear regardless of its relative rigidity.

    8-706.1.2 Evaluation and seismic improvement of unreinforced masonry bearing wall buildings shall comply with the California Existing Building Code (CEBC), Appendix Chapter A1 2013 Edition, and as modified by the CHBC.

    Exceptions:

  • CHBC § 7.47 Medium relevance — show source text

    15|7.47|7.72|8.10|8.37|8.58| |45|75|30|7.05|7.35|7.58|7.93|8.18|8.36| |44|75|31|6.95|7.23|7.45|7.77|8.00|8.16| |43|75|32|6.85|7.13|7.33|7.63|7.83|7.98| |42|75|33|6.75|7.03|7.22|7.49|7.68|7.82| |41|75|34|6.65|6.93|7.12|7.37|7.55|7.67| |46|80|34|6.65|6.93|7.12|7.37|7.55|7.67| |40|75|35|6.55|6.83|7.01|7.26|7.42|7.54| |45|80|35|6.55|6.83|7.01|7.26|7.42|7.54| |44|80|36|6.44|6.73|6.92|7.15|7.30|7.41| |43|80|37|6.32|6.63|6.82|7.05|7.19|7.30| |42|80|38|6.20|6.53|6.72|6.95|7.09|7.19| |41|80|39|6.06|6.42|6.62|6.85|6.99|7.08| |46|85|39|6.06|6.42|6.62|6.85|6.99|7.08| |40|80|40|5.91|6.30|6.52|6.76|6.89|6.98| |45|85|40|5.91|6.30|6.52|6.76|6.89|6.98| |44|85|41|5.75|6.17|6.403|6.66|6.79|6.89| |43|85|42|5.57|6.03|6.28|6.55|6.70|6.79| |42|85|43|5.37|5.88|6.16|6.44|6.59|6.69| |41|85|44|5.15|5.71|6.01|6.33|6.49|6.59| |40|85|45|4.91|5.53|5.86|6.20|6.37|6.48| |Condenser DT2|Condenser DT2|Condenser DT2|14.04|11.23|9.36|7.02|5.62|4.68| |1. LIFT = Entering Condenser Water Temperature (°F) – Leaving Chilled Water Temperature (°F)
    2.

  • CHBC § 101.5 Medium relevance — show source text

    101.5 Validity. Where a provision of this code, or the application thereof to a person or circumstance, is held invalid, the remainder of the code, or the application of such provision to other persons or circumstances, shall not be affected thereby.

    102.0 Applicability. 102.1 Conflicts Between Codes. Where the requirements within the jurisdiction of this mechanical code conflict with the requirements of the plumbing code, the plumbing code shall prevail. In instances where this code, applicable standards, or the manufacturer’s installation instructions conflict, the more stringent provisions shall prevail. Where there is a conflict between a general requirement and a specific requirement, the specific requirement shall prevail. [OSHPD 1, 1R, 2, 3, 4 & 5] See Chapter 1, Division I, Section 1.1.7

    102.2 Existing Installations. Mechanical systems lawfully in existence at the time of the adoption of this code shall be permitted to have their use, maintenance, or repair continued where the use, maintenance, or repair is in accordance with the original design and location and no hazard to life, health, or property has been created by such mechanical system.

    102.3 Maintenance. Mechanical systems, materials, and appurtenances, both existing and new, of a premise under the Authority Having Jurisdiction shall be maintained in operating condition. Devices or safeguards required by this code shall be maintained in accordance with the code edition under

    which installed.

    The owner or the owner’s designated agent shall be responsible for maintenance of mechanical systems. To determine compliance with this subsection, the Authority Having Jurisdiction shall be permitted to cause a mechanical system to be reinspected.

    102.3.1 Commercial HVAC Systems. Commercial HVAC systems both existing and new, and parts thereof shall be inspected and maintained in operating condition in accordance with ASHRAE/ACCA 180. The owner or the owner’s designated agent shall be responsible for maintenance of mechanical systems and equipment. To determine compliance with this subsection, the Authority Having Jurisdiction shall be permitted to cause a HVAC system to be reinspected. 102.3.2 Residential HVAC Systems. Residential HVAC systems both existing and new, and parts thereof shall be inspected in accordance with ACCA 4 QM. The owner or the owner’s designated agent shall be responsible for maintenance of mechanical systems and equipment. To determine compliance with this subsection, the Authority Having Jurisdiction shall be permitted to cause a HVAC system to be reinspected.

    102.4 Additions, Alterations, Renovations, or Repairs. Additions, alterations, renovations, or repairs shall conform to that required for a new system without requiring the existing mechanical system to be in accordance with the requirements of this code. Additions, alterations, renovations, or repairs shall not cause an existing system to become unsafe, insanitary or overloaded.

    Additions, alterations, renovations, or repairs to existing mechanical system installations shall comply with the provisions for new construction, unless such deviations are found to be necessary and are first approved by the Authority Having Jurisdiction. 102.5 Health and Safety. Where compliance with the provisions of this code fails to eliminate or alleviate a nuisance, or other dangerous or insanitary condition that involves health or safety hazards, the owner or the owner’s agent shall install such additional mechanical system facilities or shall make such repairs or alterations as ordered by the Authority Having Jurisdiction. **102.6 Changes in Building Occupancy.

  • CHBC § 1507.7.8 Medium relevance — show source text

    1507.7.8 Additional requirements. [DSA-SS & DSA-SS/CC, OSHPD 1, 1R, 2, 4 & 5] In addition to the requirements of Section 1507.7.5, the installation of slate shingle roof coverings shall comply with the requirements of Sections 1507.3.6 and 1507.3.7, and the seismic anchorage provisions of Section 1513.

    1507.8 Wood shingles. The installation of wood shingles shall comply with the provisions of this section and Table 1507.8.

    TABLE 1507.8—WOOD SHINGLE AND SHAKE INSTALLATION Col2 Col3
    ROOF ITEM WOOD SHINGLES WOOD SHAKES
    1. Roof slope Wood shingles shall be installed on slopes of
    not less than 3 units vertical in 12 units hori-
    zontal (3:12).
    Wood shakes shall be installed on slopes of not less
    than 4 units vertical in 12 units horizontal (4:12).
    2. Deck requirement 2. Deck requirement 2. Deck requirement
    Temperate climate Shingles shall be applied to roofs with solid or
    spaced sheathing. Where spaced sheathing is
    used, sheathing boards shall be not less than
    1″ × 4″ nominal dimensions and shall be
    spaced on centers equal to the weather expo-
    sure to coincide with the placement of
    fasteners.
    Shakes shall be applied to roofs with solid or spaced
    sheathing. Where spaced sheathing is used, sheath-
    ing boards shall be not less than 1″ × 4″ nominal
    dimensions and shall be spaced on centers equal to
    the weather exposure to coincide with the placement
    of fasteners. Where 1″ × 4″ spaced sheathing is
    installed at 10 inches, boards must be installed
    between the sheathing boards.
    In areas where the average daily
    temperature in January is 25°F or
    less or where there is a possibility
    of ice forming along the eaves
    causing a backup of water.
    Solid sheathing is required. Solid sheathing is required.
    3. Interlayment No requirements. Interlayment shall comply with ASTM D226, Type 1.
    4. Underlayment 4. Underlayment 4. Underlayment
    Temperate climate Underlayment shall comply with Section
    1507.1.1.
    Underlayment shall comply with Section 1507.1.1.
    5. Application 5. Application 5. Application
    Attachment Fasteners for wood shingles shall be hot-
    dipped galvanized or Type 304 (Type 316 for
    coastal areas) stainless steel with a minimum
    penetration of 0.75 inch into the sheathing.
    For sheathing less than 0.5 inch thick, the
    fasteners shall extend through the sheathing.
    Fasteners for wood shakes shall be hot-dipped galva-
    nized or Type 304 (Type 316 for coastal areas) with a
    minimum penetration of 0.75 inch into the sheath-
    ing. For sheathing less than 0.5 inch thick, the
    fasteners shall extend through the sheathing.
    No.
  • CHBC § 0.42 Medium relevance — show source text

    Spacing of fasteners not included in this table shall be based on Table R602.3(2).
    f. For wood structural panel roof sheathing attached to gable end roof framing and to intermediate supports within 48 inches of roof edges and ridges, nails shall be spaced at 4
    inches on center where the ultimate design wind speed is greater than 130 mph in Exposure B or greater than 110 mph in Exposure C. Fastener spacing applies where roof
    framing specific gravity is 0.42 or larger. Where roof framing specific gravity is greater than or equal to 0.35 but less than 0.42 in accordance with AWC NDS, fastening of roof
    sheathing shall be with RSRS-03 (21/2″ × 0.131″ × 0.281″ head) nails.
    g. Gypsum sheathing shall conform to ASTM C1396 and shall be installed in accordance with ASTM C1280 or GA 253 . Fiberboard sheathing shall conform to ASTM C208.
    h. Spacing of fasteners on floor sheathing panel edges applies to panel edges supported by framing members and required blocking and at floor perimeters only. Spacing of fasteners
    on roof sheathing panel edges applies to panel edges supported by framing members and required blocking. Blocking of roof or floor sheathing panel edges perpendicular to the
    framing members need not be provided except as required by other provisions of this code. Floor perimeter shall be supported by framing members or solid blocking.
    i. Where a rafter is fastened to an adjacent parallel ceiling joist in accordance with this schedule, provide two toe nails on one side of the rafter and toe nails from the ceiling joist
    to top plate in accordance with this schedule. The toe nail on the opposite side of the rafter shall not be required.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s; 1 ksi = 6.895 MPa.
    a. Nails are smooth-common, box or deformed shanks except where otherwise stated. Nails used for framing and sheathing connections are carbon steel and shall have mini-
    mum average bending yield strengths as shown: 80 ksi for shank diameter of 0.192 inch (20d common nail), 90 ksi for shank diameters larger than 0.142 inch but not larger than
    0.177 inch, and 100 ksi for shank diameters of 0.142 inch or less. Connections using nails and staples of other materials, such as stainless steel, shall be designed by accepted
    engineering practice or approved under Section R104.2.2.
    b. RSRS-01 is a Roof Sheathing Ring Shank nail meeting the specifications in ASTM F1667.
    c. Nails shall be spaced at not more than 6 inches on center at all supports where spans are 48 inches or greater.
    d. Four-foot by 8-foot or 4-foot by 9-foot panels shall be applied vertically.
    e. Spacing of fasteners not included in this table shall be based on Table R602.3(2).
    f. For wood structural panel roof sheathing attached to gable end roof framing and to intermediate supports within 48 inches of roof edges and ridges, nails shall be spaced at 4
    inches on center where the ultimate design wind speed is greater than 130 mph in Exposure B or greater than 110 mph in Exposure C. Fastener spacing applies where roof
    framing specific gravity is 0.42 or larger.

  • CHBC § 6.44 Medium relevance — show source text

    17|6.44|6.66|6.99|7.23|7.40| |45|75|30|6.08|6.34|6.54|6.84|7.06|7.22| |44|75|31|6.00|6.24|6.43|6.71|6.90|7.05| |43|75|32|5.91|6.15|6.33|6.58|6.76|6.89| |42|75|33|5.83|6.07|6.23|6.47|6.63|6.75| |41|75|34|5.74|5.98|6.14|6.36|6.51|6.62| |46|80|34|5.74|5.98|6.14|6.36|6.51|6.62| |40|75|35|5.65|5.90|6.05|6.26|6.40|6.51| |45|80|35|5.65|5.90|6.05|6.26|6.40|6.51| |44|80|36|5.56|5.81|5.97|6.17|6.30|6.40| |43|80|37|5.46|5.73|5.89|6.08|6.21|6.30| |42|80|38|5.35|5.64|5.80|6.00|6.12|6.20| |41|80|39|5.23|5.54|5.71|5.91|6.03|6.11| |46|85|39|5.23|5.54|5.71|5.91|6.03|6.11| |40|80|40|5.10|5.44|5.62|5.83|5.95|6.03| |45|85|40|5.10|5.44|5.62|5.83|5.95|6.03| |44|85|41|4.96|5.33|5.55|5.74|5.86|5.94| |43|85|42|4.81|5.21|5.42|5.66|5.78|5.86| |42|85|43|4.63|5.08|5.31|5.56|5.69|5.77| |41|85|44|4.45|4.93|5.19|5.46|5.60|5.69| |40|85|45|4.24|4.77|5.06|5.35|5.50|5.59| |Condenser DT2|Condenser DT2|Condenser DT2|14.04|11.23|9.36|7.02|5.62|4.68| |1. LIFT = Entering Condenser Water Temperature (°F) – Leaving Chilled Water Temperature (°F)
    2.

Frequently asked questions

Can existing HVAC or fuel‑burning systems be left in place under the CHBC?

Yes. The CHBC permits existing mechanical systems to remain in use when, in the enforcing agency’s opinion, they do not constitute a safety hazard; the agency may also approve alternative solutions that provide equivalent life safety .

Are historical buildings exempt from energy‑efficiency rules when modifying mechanical systems?

Qualified historical buildings are exempted from energy conservation standards under the CHBC, but when new nonhistorical HVAC or space‑conditioning components are installed they must comply with Title 24, Part 6 unless compliance would threaten character‑defining historical features .

May original masonry chimneys and vents be reused for fuel‑burning appliances?

Masonry chimneys that are structurally sound may remain in use after evaluation and documentation; however, certain vents (e.g., terra cotta or concealed Type C metallic vents) may require mitigation or case‑by‑case approval before reuse .

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