Chapter 1 — GENERAL CODE PROVISIONS
507.7 Pharmaceutical Compounding
California Mechanical Code (Title 24, Part 4) · 2025 edition · updated 2026-09-10 · California
Italicized text is a California amendment to the model code, as printed in the official publication.
Exhaust Discharge . . . . . . . . . . . . 111
508.0 Type I Hoods . . . . . . . . . . . . . . . . 111
508.1 Where Required . . . . . . . . . . . . . . 111
508.2 Listed Type I Hood Assemblies . . 111
508.3 Construction of Type I Hoods . . . . 111
508.4 Supports . . . . . . . . . . . . . . . . . . . . 112
508.5 Hood Size . . . . . . . . . . . . . . . . . . . 112
Table 508.5.1.2 Extra-Heavy-Duty Cooking Appliance Airflow . . . . . . . . . . . . . 113
Table 508.5.1.3 Heavy-Duty Cooking Appliance
Airflow. . . . . . . . . . . . . . . . . . . . . . 113
Table 508.5.1.4 Medium-Duty Cooking Appliance
Airflow. . . . . . . . . . . . . . . . . . . . . . 113
Table 508.5.1.5 Light-Duty Cooking Appliance
Airflow. . . . . . . . . . . . . . . . . . . . . . 113
508.6 Solid-Fuel Hood Assemblies . . . . 114
508.7 Exhaust Outlets . . . . . . . . . . . . . . 114
509.0 Grease Removal Devices in
Hoods . . . . . . . . . . . . . . . . . . . . . . 114
509.1 Grease Removal Devices. . . . . . . 114
509.2 Installation . . . . . . . . . . . . . . . . . . 114
509.3 Solid-Fuel Grease Removal
Devices. . . . . . . . . . . . . . . . . . . . . 115
510.0 Exhaust Duct Systems . . . . . . . . . 115
510.1 General. . . . . . . . . . . . . . . . . . . . . 115
510.2 Clearance . . . . . . . . . . . . . . . . . . . 115
510.3 Openings . . . . . . . . . . . . . . . . . . . 115
510.4 Listed Grease Ducts . . . . . . . . . . . 116
510.5 Other Grease Ducts . . . . . . . . . . . 116
510.6 Exterior Installations . . . . . . . . . . . 117
510.7 Interior Installations . . . . . . . . . . . 118
510.8 Underground Installations. . . . . . . 118
510.9 Termination of Type I Hood Exhaust System . . . . . . . . . . . . . . 119
510.10 Solid-Fuel Duct Systems . . . . . . . 120
511.0 Air Movement . . . . . . . . . . . . . . . . 120
511.1 Exhaust Fans for Commercial
Cooking Operations . . . . . . . . . . . 120
511.2 Airflow. . . . . . . . . . . . . . . . . . . . . . 121
511.3 Makeup Air . . . . . . . . . . . . . . . . . . 122
511.4 Common Duct (Manifold) Systems . . . . . . . . . . . . . . . . . . . . 122
511.5 Solid-Fuel Air Movement
Requirements . . . . . . . . . . . . . . . . 122
512.0 Auxiliary Equipment . . . . . . . . . . . 122
512.1 Dampers . . . . . . . . . . . . . . . . . . . . 122
512.2 Electrical Equipment. . . . . . . . . . . 122
512.3 Other Equipment . . . . . . . . . . . . . 123
512.4 Solid-Fuel Auxiliary Equipment. . . 123
513.0 Fire-Extinguishing Equipment. . . . 123
513.1 General. . . . . . . . . . . . . . . . . . . . . 123
513.2 Types of Equipment . . . . . . . . . . . 123
513.3 Simultaneous Operation . . . . . . . . 124
513.4 Fuel and Electric Power Shutoff . . 125
513.5 Manual Actuation . . . . . . . . . . . . . 125
513.6 System Annunciation . . . . . . . . . . 125
513.7 Special Design and Application . . 125
513.8 Review and Certification. . . . . . . . 125
513.9 Installation Requirements . . . . . . . 125
513.10 Portable Fire Extinguishers . . . . . 125
513.11 Maintenance . . . . . . . . . . . . . . . . . 125
513.12 Solid-Fuel Fire-Extinguishing Equipment . . . . . . . . . . . . . . . . . . 126
514.0 Procedures for the Use, Inspection, Testing, and Maintenance of Equipment. . . . . . 126
514.1 Operating Procedures . . . . . . . . . 126
514.2 Inspection, Testing and Maintenance . . . . . . . . . . . . . . . . . 126
514.3 Inspection for Grease Buildup . . . 126
Table 514.3 Schedule of Inspection for Grease Buildup. . . . . . . . . . . . . . . 126
514.4 Cleaning of Exhaust Systems. . . . 126
514.5 Cooking Equipment Maintenance . 127
515.0 Minimum Safety Requirements for Cooking Equipment . . . . . . . . . 127
515.1 Cooking Equipment . . . . . . . . . . . 127
515.2 Operating Controls . . . . . . . . . . . . 128
TABLE OF CONTENTS
516.0 Recirculating Systems . . . . . . . . . 128
516.1 General Requirements . . . . . . . . . 128
516.2 Design Restrictions. . . . . . . . . . . . 128
516.3 Interlocks . . . . . . . . . . . . . . . . . . . 129
516.4 Location and Application Restrictions. . . . . . . . . . . . . . . . . . 129
516.5 Additional Fire Safety Requirements . . . . . . . . . . . . . . . . 129
516.6 Use and Maintenance. . . . . . . . . . 129
517.0 Solid-Fuel Cooking Operations. . . 129
517.1 Venting Application. . . . . . . . . . . . 129
517.2 Location of Appliances . . . . . . . . . 130
517.3 Hoods for Solid-Fuel Cooking. . . . 130
517.4 Exhaust Systems for Solid-Fuel Cooking . . . . . . . . . . . . 130
517.5 Grease Removal Devices
for Solid-Fuel Cooking . . . . . . . . . 130
517.6 Air Movement for Solid-Fuel
Cooking . . . . . . . . . . . . . . . . . . . . 130
517.7 Fire-Extinguishing Equipment for Solid-Fuel Cooking . . . . . . . . . 131
517.8 Other Safety Requirements . . . . . 131
518.0 Downdraft Appliances. . . . . . . . . . 131
518.1 General. . . . . . . . . . . . . . . . . . . . . 131
518.2 Ventilation System . . . . . . . . . . . . 132
518.3 Fire-Extinguishing Equipment. . . . 132
518.4 Airflow Switch or Transducer . . . . 132
518.5 Surface Materials . . . . . . . . . . . . . 132
519.0 Type II Hood Exhaust System Requirements . . . . . . . . . . . . . . . . 132
519.1 Where Required . . . . . . . . . . . . . . 132
519.2 Construction of Type II Hoods . . . 132
519.3 Type II Hood Exhaust System Net Airflow . . . . . . . . . . . . . . . . . . 132
519.4 Type II Exhaust Duct Systems . . . 132
519.5 Termination of Type II Hood Exhaust System . . . . . . . . . . . . . . 132
519.6 Makeup Air . . . . . . . . . . . . . . . . . . 133
519.7 Independent Exhaust Duct System . . . . . . . . . . . . . . . . . 133
CHAPTER 6 DUCT SYSTEMS . . . . . . . . . . . . . 135
601.0 General. . . . . . . . . . . . . . . . . . . . . 137
601.1 Applicability. . . . . . . . . . . . . . . . . . 137
601.2 Sizing Requirements . . . . . . . . . . 137
602.0 Material. . . . . . . . . . . . . . . . . . . . . 137
602.1 General. . . . . . . . . . . . . . . . . . . . . 137
602.2 Combustibles Within Ducts or
Plenums . . . . . . . . . . . . . . . . . . . . 137
602.3 Tall Wood (Mass Timber) Buildings . . . . . . . . . . . . . . . . . . . . 137
602.4 Metallic . . . . . . . . . . . . . . . . . . . . . 138
602.5 Nonmetallic Ducts. . . . . . . . . . . . . 138
602.6 Vibration Isolators. . . . . . . . . . . . . 138
602.7 Corridors. . . . . . . . . . . . . . . . . . . . 138
603.0 Installation of Ducts . . . . . . . . . . . 138
603.1 General. . . . . . . . . . . . . . . . . . . . . 138
603.2 Under-Floor or Crawl Space. . . . . 138
603.3 Metal Ducts. . . . . . . . . . . . . . . . . . 138
603.4 Flexible Air Ducts . . . . . . . . . . . . . 138
603.5 Plastic Ducts. . . . . . . . . . . . . . . . . 139
603.6 Protection of Ducts . . . . . . . . . . . . 139
603.7 Support of Ducts. . . . . . . . . . . . . . 139
603.8 Protection Against Flood Damage . 139
603.9 Joints and Seams of Ducts. . . . . . 139
Table 603.9.1 Closure Markings . . . . . . . . . . . . . 140
603.10 Cross Contamination . . . . . . . . . . 140
603.11 Underground Installation . . . . . . . 140
603.12 Air Dispersion Systems . . . . . . . . 140
603.13 Clearances . . . . . . . . . . . . . . . . . . 140
604.0 Furnace Plenums and Air Ducts
Used in Fuel-Gas Appliances . . . . 141
604.1 Furnace Plenums and Air Ducts. . 141
604.2 Supplied as a Part of Furnace . . . 141
604.3 Not Supplied with the Furnace . . . 141
604.4 Return Air . . . . . . . . . . . . . . . . . . . 141
605.0 Insulation of Ducts . . . . . . . . . . . . 141
605.1 General. . . . . . . . . . . . . . . . . . . . . 141
606.0 Smoke Dampers, Fire Dampers, and Ceiling Dampers . . . . . . . . . . 142
606.1 Smoke Dampers. . . . . . . . . . . . . . 142
606.2 Fire Dampers . . . . . . . . . . . . . . . . 142
606.3 Ceiling Radiation Dampers. . . . . . 142
606.4 Combination Fire/Smoke
Dampers . . . . . . . . . . . . . . . . . . . . 142
606.5 Corridor Dampers . . . . . . . . . . . . . 142
606.6 Periodic Testing and Inspection . . 142
606.7 Multiple Arrangements . . . . . . . . . 142
606.8 Access and Identification . . . . . . . 142
606.9 Freedom from Interference. . . . . . 142
606.10 Temperature Classification of Operating Elements . . . . . . . . . 142
607.0 Ventilating Ceilings . . . . . . . . . . . . 142
607.1 General. . . . . . . . . . . . . . . . . . . . . 142
607.2 Requirements . . . . . . . . . . . . . . . . 142
608.0 Use of Under-Floor Space as Supply Plenum for Dwelling Units. . 143
TABLE OF CONTENTS
608.1 General. . . . . . . . . . . . . . . . . . . . . 143
608.2 Dwelling Units. . . . . . . . . . . . . . . . 143
608.3 Enclosed. . . . . . . . . . . . . . . . . . . . 143
608.4 Flammable Materials . . . . . . . . . . 143
608.5 Access . . . . . . . . . . . . . . . . . . . . . 143
608.6 Automatic Control . . . . . . . . . . . . . 143
608.7 Temperature Limit . . . . . . . . . . . . 143
608.8 Noncombustible Receptacle. . . . . 143
608.9 Floor Registers . . . . . . . . . . . . . . . 143
608.10 Exterior Wall and Interior Stud
Partitions. . . . . . . . . . . . . . . . . . . . 143
608.11 Wall Register . . . . . . . . . . . . . . . . 143
608.12 Distance from Combustible . . . . . 143
608.13 Vapor Barrier . . . . . . . . . . . . . . . . 143
608.14 Prohibited . . . . . . . . . . . . . . . . . . . 143
609.0 Automatic Shutoffs . . . . . . . . . . . . 143
609.1 Air-Moving Systems and Smoke Detectors . . . . . . . . . . . . . . . . . . . 143
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Ask AI about this code▸Contents — California Mechanical Code (Title 24, Part 4)
▸Chapter 1 — GENERAL CODE PROVISIONS
Overview- 301.7 OSHPD 1R . . . . . . . . . . . . . . . . . . . 51
- 306.2 Building Automation Systems . . . . 56
- 311.5 California Energy Code
- 318.1 Applicability . . . . . . . . . . . . . . . . . . 60
- 318.2 Services/Systems and Utilities . . . . 60
- 319.1 Requirements for Hospitals and
- 319.2 Requirements for Skilled
- 320.1 Requirements for Hospitals and
- 320.2 Requirements for Skilled
- 320.3 Requirements for Outpatient
- 320.4 Telephone and Technology
- 320.5 Psychiatric Services. . . . . . . . . . . . 61
- 401.3 Filters . . . . . . . . . . . . . . . . . . . . . . . 69
- 407.1 General. . . . . . . . . . . . . . . . . . . . . . 78
- 407.2 Outdoor Air Intakes and
- 407.3 Air Balance. . . . . . . . . . . . . . . . . . . 78
- 407.4 Air Circulation . . . . . . . . . . . . . . . . . 78
- 407.5 Variable Air Volume . . . . . . . . . . . . 79
- 407.6 Economizers. . . . . . . . . . . . . . . . . . 79
- 407.7 Unoccupied Turndown. . . . . . . . . . 79
- 407.8 Building Pressurization . . . . . . . . . 80
- 408.1 General. . . . . . . . . . . . . . . . . . . . . . 80
- 408.2 Filters for Hospitals. . . . . . . . . . . . . 80
- 408.3 Filters for Skilled Nursing
- 408.4 Filters for Outpatient Facilities . . . . 80
- 408.5 Filters for Recirculating
- 410.1 Laboratory Ventilating Systems . . . 80
- 410.2 Exhaust Hoods and
- 410.3 Laboratory Fume Hoods . . . . . . . . 80
- 414.1 Exhaust Systems . . . . . . . . . . . . . . 81
- 414.2 Air Distribution . . . . . . . . . . . . . . . . 81
- 415.1 Air Distribution . . . . . . . . . . . . . . . . 82
- 418.1 Air Changes . . . . . . . . . . . . . . . . . . 82
- 418.2 Exhaust Requirements . . . . . . . . . . 82
- 418.3 Ventilation Requirements . . . . . . . . 82
- 418.4 Gas Valves . . . . . . . . . . . . . . . . . . . 82
- 418.5 Alarm Systems . . . . . . . . . . . . . . . . 83
- 419.1 Formula Preparation Area . . . . . . . 83
- 419.2 Treatment Area/Room . . . . . . . . . . 83
- 505.12 Pharmacies – Compounding
- 507.7 Pharmaceutical Compounding
- 609.2 Air-Moving Systems and
- 1602.2 Liquid-Fueled Engines and
- 104.2 Items (1) through (5) of this code.
- 101.1 Title. This document shall be known as the “Uniform
- 101.2 Scope. The provisions of this code shall apply to the
- 101.3 Purpose. This code is an ordinance providing minimum req…
- 101.4 Unconstitutional. Where a section, subsection, sentence,…
- 101.5 Validity. Where a provision of this code, or the applica…
- 102.1 Conflicts Between Codes. Where the requirements
- 102.2 Existing Installations. Mechanical systems lawfully
- 102.3 Maintenance. Mechanical systems, materials, and
- 102.4 Additions, Alterations, Renovations, or
- 102.5 Health and Safety. Where compliance with the provisions …
- 102.6 Changes in Building Occupancy. Mechanical
- 102.7 Moved Structures. Parts of the mechanical system of
- 102.8 Appendices. The provisions in the appendices are
- 103.1 General. The Authority Having Jurisdiction shall be
- 103.2 Liability. The Authority Having Jurisdiction charged
- 103.3 Applications and Permits. The Authority Having
- 103.4 Right of Entry. Where it is necessary to make an
- 104.1 Permits Required. It shall be unlawful for a person,
- 104.2 Exempt Work. A permit shall not be required for the
- 104.3 Application for Permit. To obtain a permit, the
- 104.4 Permit Issuance. The application, construction documents…
- 104.5 Fees. Fees shall be assessed in accordance with the
- 105.1 General. Mechanical systems for which a permit is
- 105.2 Required Inspections. New mechanical system
- 105.3 Testing of Systems. Mechanical systems shall be
- 105.4 Connection to Service Utilities. No person shall
- 106.1 General. It shall be unlawful for a person, firm, or
- 106.2 Notices of Correction or Violation. Notices of
- 106.3 Penalties. A person, firm, or corporation violating a
- 106.4 Stop Orders. Where work is being done contrary to
- 106.5 Authority to Disconnect Utilities in Emergen-
- 106.6 Authority to Condemn. Where the Authority Having Jurisdi…
- 107.1 General. In order to hear and decide appeals of orders,
- 107.2 Limitations of Authority. The Board of Appeals
- Chapter 2 — DEFINITIONS
- Chapter 3 — GENERAL REGULATIONS
- Chapter 4 — VENTILATION AIR
- Chapter 5 — EXHAUST SYSTEMS
- Chapter 6 — DUCT SYSTEMS
- Chapter 7 — COMBUSTION AIR
- Chapter 8 — CHIMNEYS AND VENTS
- Chapter 9 — INSTALLATION OF SPECIFIC APPLIANCES
- Chapter 10 — BOILERS AND PRESSURE VESSELS
- Chapter 11 — REFRIGERATION
- Chapter 12 — HYDRONICS
- Chapter 13 — FUEL GAS PIPING
- Chapter 14 — PROCESS PIPING
- Chapter 15 — SOLAR ENERGY SYSTEMS
- Chapter 16 — STATIONARY POWER PLANTS
- Chapter 17 — GEOTHERMAL ENERGY SYSTEMS AND AMBIENT TEMPERATURE…
- Chapter 18 — REFERENCED STANDARDS
- Appendix A — RESIDENTIAL PLAN EXAMINER REVIEW FORM FOR HVAC SY…
- Appendix B — PROCEDURES TO BE FOLLOWED TO PLACE GAS EQUIPMENT …
- Appendix C — INSTALLATION AND TESTING OF OIL (LIQUID) FUEL-FIR…
- Appendix D — FUEL SUPPLY: MANUFACTURED/MOBILE HOME PARKS AND R…
- Appendix E — SUSTAINABLE PRACTICES
- Appendix F — SIZING OF VENTING SYSTEMS AND OUTDOOR COMBUSTION …
- Appendix G — EXAMPLE CALCULATION OF OUTDOOR AIR RATE
- Appendix H — PROFESSIONAL QUALIFICATIONS
- Appendix I — INDOOR HORTICULTURAL FACILITIES
- Appendix J — CLEAN AIR DELIVERY