CRSC · California Referenced Standards Code

What guidance covers shielding for accelerators/particle facilities?

If you are building or altering an accelerator or particle facility in California, the California Referenced Standards Code requires you to design all shielding using the National Council on Radiation Protection and Measurements reports — specifically Report No. 51 for 0.1–100 MeV accelerators (see **§ 12-31C-101**).

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Last reviewed: July 6, 2026

What the code requires — 2-4 sentences

All radiation shielding for rooms and enclosures that house radiation machines must follow the mandatory standards and appendices listed in the California Referenced Standards Code. The controlling rule is § 12-31C-101, which requires compliance with NCRP Report No. 35, No. 49 and specifically Report No. 51: "Radiation Protection Design Guidelines for 0.1–100 MeV Particle Accelerator Facilities."

Shielding for particle accelerators must be designed using the mandatory NCRP references (Reports 35, 49 and especially Report 51); the CRSC does not provide alternate thickness tables — follow those reports.

Requirements in detail

Key defined terms (from Chapter 31C, used in the regulatory context) — first mention in bold:
- PRIMARY PROTECTIVE BARRIER — barrier to attenuate the useful beam.
- SECONDARY PROTECTIVE BARRIER — barrier to attenuate stray radiation.
- STRAY RADIATION — radiation not serving any useful purpose (leakage, scatter).
- USEFUL BEAM — the radiation that passes through the tube/beam aperture.
Mandatory design standard: The CRSC text does not itself give formulas, barrier thicknesses, or step-by-step shielding calculations. Instead it makes the NCRP reports mandatory design references:
- NCRP Report No. 35 — Dental X‑ray Protection.
- NCRP Report No. 49 — Structural Shielding Design and Evaluation for medical x‑ and gamma rays up to 10 MeV.
- NCRP Report No. 51 — Radiation Protection Design Guidelines for 0.1–100 MeV Particle Accelerator Facilities (the particle-accelerator specific guide). § 12-31C-101 points designers to these documents.
Authority and variance: The Building Code cross-references § 12-31C-101 as the required standard for shielding barriers in machine rooms; only the Department of Health Services may grant a variance to the referenced standards.

Decision-relevant dimensions (quick reference table)

Decision dimension	Typical value or entry	How it affects the design	Code Reference
Facility type	Particle accelerator (cyclotron, linac)	Use NCRP Report No. 51 for shielding methodology	§ 12-31C-101
Energy range to design for	0.1–100 MeV (particle accelerators)	Determines which scattering/attenuation models and secondary radiation (neutrons, photoneutrons) to include	§ 12-31C-101 (Report No. 51 title)
Other machine types	Diagnostic/therapeutic X‑ray up to 10 MeV	Use NCRP Report No. 49	§ 12-31C-101
Who may vary requirements	Department of Health Services only	Variance requests go to DPH (only agency authorized)	CBC § 3102C referencing § 12-31C-101
Responsibility for final shielding spec	Qualified/certified medical physicist or radiation physicist (practice-level requirement shown elsewhere in CBC for medical uses)	Physicist produces shielding report incorporated into construction documents (see related provisions)	See § 12-31C-101 + CBC references

Notes:

The CRSC (Sec. § 12-31C-101) makes Reports 35/49/51 mandatory; it does not reproduce the technical tables or formulas from those reports. All specific attenuation calculations, occupancy factors, workload definitions, and secondary-radiation treatments must come from those NCRP documents.

Exceptions & special cases

The CRSC text does not list technical exceptions inside § 12-31C-101; it simply mandates the NCRP reports. Any technical exceptions, alternate methods or simplified rules would have to be justified per the NCRP reports or by an approved variance from the Department of Health Services.
Local building/permitting authorities implement Chapter 31C (CBC) and require that shielding designs reference § 12-31C-101; the CBC also states that only DPH may grant a variance from those standards. Do not assume local code replaces the NCRP methods — they enforce them.

Common mistakes

Assuming the CRSC contains numerical thickness tables or step-by-step shielding calculations. It does not — § 12-31C-101 delegates that to NCRP Reports 35, 49 and 51. Designers must consult those documents for numbers and methods.
Designing shielding without a qualified radiation physicist’s report where required. For medical therapy and nuclear medicine the CBC requires a certified physicist to specify protection to be installed and incorporated into construction documents — that obligation applies in practice when NCRP-based shielding is required.
Requesting a variance at the local level: only the Department of Health Services can grant variances from the CRSC radiation shielding standards — do not rely on local code officials to authorize alternate methods without DPH approval.

Worked example — concrete scenario (illustrative)

The CRSC requires using NCRP Report No. 51 for particle accelerators — the example below illustrates how to apply that requirement. Because § 12-31C-101 makes Report 51 mandatory, exact attenuation numbers must come from that report; the numeric values below are illustrative only and must be replaced by calculations from Report 51 for any real design.

Scenario (illustrative):

Install a clinical linac that operates at 18 MeV electrons producing therapeutic x‑rays and photoneutrons (secondary radiation likely above ~10 MeV).
Design objective: limit public dose to 0.02 mSv/week (example design goal; actual design goals must be set per the applicable regulatory dose limits and NCRP guidance).

Illustrative application steps:

Identify applicable NCRP method: because the machine energy is in the tens of MeV, follow NCRP Report No. 51 methods for primary/secondary barriers and for neutron shielding. (Mandated by § 12-31C-101.)
From Report 51 (illustrative only), determine:
- Workload (MU/week or dose rate at isocenter),
- Use factor (fraction of time beam points at a given barrier),
- Occupancy factor for the area beyond the barrier,
- Distance to the point of interest, and
- Acceptable design dose (e.g., 0.02 mSv/week).
Plug those inputs into the NCRP Report 51 formulae to compute required attenuation for the primary barrier, then check secondary barriers (leakage, scatter) and neutron shielding. The output will be required barrier thicknesses and material choices (concrete, steel, borated materials for neutrons).
Prepare a physicist shielding report that documents all inputs, calculations and final recommended barrier materials and thicknesses; include the report in construction documents for permitting. The CBC requires that radiation protection requirements be incorporated into construction documents (see related CBC provisions).

Important: do not use the illustrative numbers above to build shielding — the CRSC mandates use of NCRP Report No. 51 for the real calculations (see § 12-31C-101).

Related provisions

§ 12-31C-101 — Mandatory use of NCRP Reports 35, 49 and 51 for shielding design (primary controlling CRSC text).
§ 31C-3102C — CBC: "All radiation shielding barriers in rooms and enclosures housing machines shall meet the requirements of Section 12-31C-101..." (ties the CBC to the CRSC requirement; only DPH may grant variances).
CBC provisions requiring a certified physicist to specify location/amount of protection for many radiation therapy and nuclear medicine areas (e.g., Section 1224.34.1.1) — this practice-level requirement is relevant when applying the NCRP methods required by § 12-31C-101.

Code references

Grounded in the retrieved California Referenced Standards Code — click a citation to read the verbatim passage:

CRSC § 1.11. High relevance — show source text
The state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.

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31C [DPH] RADIATION

SECTION 3101C—SCOPE

For the purpose of this chapter, the following terms shall have the meaning indicated:

PRIMARY PROTECTIVE BARRIER is a barrier to attenuate the useful beam.

SECONDARY PROTECTIVE BARRIER is a barrier to attenuate stray radiation.

STRAY RADIATION is radiation not serving any useful purpose, which includes leakage and scattered radiation.

USEFUL BEAM is the radiation which passes through the window, aperture, cone or other collimating device of the tube housing.

SECTION 3102C—RADIATION SHIELDING BARRIERS

All radiation shielding barriers in rooms and enclosures housing machines shall meet the requirements of Section 12-31C-101, Chapter 12-31C, Part 12, California Referenced Standards Code. The Department of Health Services is the only agency that may grant a variance or exception to these standards.

SECTION 3103C—MEDICAL RADIOGRAPHIC AND PHOTOFLUOROGRAPHIC INSTALLATIONS

3103C.1 Operator station. The operator’s station at the control shall be behind a protective barrier either in a separate room, in a protected booth or behind a shield which will intercept the useful beam and any radiation which has been scattered only once.

3103C.2 Patient observation and communication. Provision shall be made for the operator to observe and communicate with the patient without leaving the shielded position at the control panel. When an observation window is used, it must provide radiation atten- uation equal to that required in the surrounding barrier.

SECTION 3104C—MEDICAL THERAPEUTIC X-RAY INSTALLATIONS

3104C.1 General. All wall, floor and ceiling areas that can be struck by the useful beam, plus a border of 1 foot (305 mm), shall be provided with primary protective barriers.

3104C.2 Equipment operating above 50 kVp. Equipment operating above 50 kVp shall conform with the following: 1. The control station shielding shall either be an integral part of the building or anchored to the building. 2. The control station shall be provided with a window having radiation attenuation equal to that required by the adjacent barrier, or a mirror system, or a closed-circuit television viewing screen. The patient area must be visible to the operator with- out having to leave the protected area during exposure.
CRSC § 1224.34.3.2 High relevance — show source text
but otherwise having the_ same functional characteristics as the above mega-voltage units and conforming to the requirements of Chap- ter 31C and the California Radiation Control Regulations, California Code of Regulations, Title 17, Division 1, Chapter 5, Subchapter 4. 5.3. Direct access to space provided for brachytherapy equipment which shall meet the requirements of Chapter 31C and the California Radiation Control Regulations, California Code of Regulations, Title 17, Division 1, Chap- ter 5, Subchapter 4. 5.4. Shielding of the rooms shall meet the requirements of Chapter 31C and the California Radiation Control Regula- tions. California Code of Regulations, Title 17, Division 1, Chapter 5, Subchapter 4.

1224.34.3.2 Radiation protection. Cobalt, linear accelerators, hot lab and high dose rate brachytherapy rooms and simulation rooms require radiation protection. All rooms that provide radiation treatment shall be appropriately shielded. A certified physi- cist shall specify the type, location and amount of protection to be installed in accordance with final approved department layout and equipment selection. Radiation protection requirements shall be incorporated into the construction documents and comply with Chapter 31C and the requirements of California Radiation Control Regulations, California Code of Regulations, Title 17, Divi- sion 1, Chapter 5 and Subchapter 4.

1224.34.3.3 Room sizes. Rooms shall be sized as follows:

1. Cobalt rooms and linear accelerators shall be sized in accordance with equipment requirements and shall accommo- date a gurney for litter borne patients. Layouts shall provide for preventing the escape of radioactive particles. Openings into the room, including doors, ductwork, vents and electrical raceways and conduits, shall be baffled to prevent direct exposure to other areas of the facility. 2. Simulator, accelerator and cobalt rooms shall be sized to accommodate the equipment with patient access on a gurney, medical staff access to the equipment and patient, and service access. 3. Where a table is used, the room shall be sized to provide a minimum clearance of 4 feet (1218 mm) on three sides of the table to facilitate bed transfer and provide access to the patient. The door swing shall not encroach on the equipment space, patient circulation space or transfer space. 4. Minimum room size shall be 260 square feet (24.15 m [2] ) for the simulator room; 680 square feet (63.17 m [2] ), including the maze, for accelerator rooms; 200 square feet (18.58 m [2] ) for brachytherapy rooms; and 450 square feet (41.81 m [2] ) for cobalt rooms.

1224.34.3.4 General support area. The following areas shall be provided: 1. A gurney hold area adjacent to the treatment rooms, screened for privacy and combined with a seating area for outpatients. 2. Exam or treatment room shall be provided with a minimum of 100 square feet (9.29 m [2] ) with a minimum dimension of 8 feet (2438 mm). Each exam room shall be equipped with a handwashing station.

CRSC § 1.11. High relevance — show source text

CALIFORNIA BUILDING CODE – MATRIX ADOPTION TABLE

CHAPTER 31C – RADIATION

(Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)

Adopting agency	BSC	BSC- CG	SFM	HCD	Col6	Col7	DSA	Col9	Col10	OSHPD	Col12	Col13	Col14	Col15	Col16	Col17	BSCC	DPH	AGR	DWR	CEC	CA	SL	SLC
Adopting agency	BSC	BSC- CG	SFM	1	2	1/AC	AC	SS	SS/CC	1	1R	2	3	4	5	6	6	6	6	6	6	6	6	6
Adopt entire chapter																		X
Adopt entire chapter as amended (amended sections listed below)
Adopt only those sections that are listed below
Chapter / Section

The state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.

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31C [DPH] RADIATION

SECTION 3101C—SCOPE

For the purpose of this chapter, the following terms shall have the meaning indicated:

PRIMARY PROTECTIVE BARRIER is a barrier to attenuate the useful beam.

SECONDARY PROTECTIVE BARRIER is a barrier to attenuate stray radiation.

STRAY RADIATION is radiation not serving any useful purpose, which includes leakage and scattered radiation.

USEFUL BEAM is the radiation which passes through the window, aperture, cone or other collimating device of the tube housing.

SECTION 3102C—RADIATION SHIELDING BARRIERS

All radiation shielding barriers in rooms and enclosures housing machines shall meet the requirements of Section 12-31C-101, Chapter 12-31C, Part 12, California Referenced Standards Code. The Department of Health Services is the only agency that may grant a variance or exception to these standards.

SECTION 3103C—MEDICAL RADIOGRAPHIC AND PHOTOFLUOROGRAPHIC INSTALLATIONS

CRSC § 1224.34.2.14 High relevance — show source text
1224.34.2.14 Hot lab for scintigraphy (gamma camera), PET and SPECT facilities. A securable area or room shall be provided in which radiopharmaceuticals can be safely stored and doses can be calculated and prepared. 1. A single hot lab shall be permitted to serve multiple scanners and nuclear medicine modalities. 2. The hot lab shall be shielded in compliance with Section 1224.34.1.1. 3. A source storage area, a dose area and a storage area for syringe shields shall be provided.

1224.34.3 Radiotherapy service space.

1224.34.3.1 Radiation therapy space. If radiation therapy is provided, the following shall be accommodated: 1. Patient reception and waiting areas. 2. Space for medical and physics staff functions. 3. Space for equipment and supplies. 4. Housekeeping room. 5. Direct access to space provided for radiation measurement and calibration equipment, including a calibration constancy instrument and access to a secondary standard dose meter.

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5.1. A megavoltage treatment unit capable of delivering x-rays or gamma rays of effective energy 500 KeV or more and conforming to the requirements of Chapter 31C and the California Radiation Control Regulations, Califor- nia Code of Regulations, Title 17, Division 1, Chapter 5, Subchapter 4. 5.2. Access to a medium voltage or superficial treatment unit delivering 500 KeV or less, but otherwise having the same functional characteristics as the above mega-voltage units and conforming to the requirements of Chap- ter 31C and the California Radiation Control Regulations, California Code of Regulations, Title 17, Division 1, Chapter 5, Subchapter 4. 5.3. Direct access to space provided for brachytherapy equipment which shall meet the requirements of Chapter 31C and the California Radiation Control Regulations, California Code of Regulations, Title 17, Division 1, Chap- ter 5, Subchapter 4. 5.4. Shielding of the rooms shall meet the requirements of Chapter 31C and the California Radiation Control Regula- tions. California Code of Regulations, Title 17, Division 1, Chapter 5, Subchapter 4.

1224.34.3.2 Radiation protection. Cobalt, linear accelerators, hot lab and high dose rate brachytherapy rooms and simulation rooms require radiation protection. All rooms that provide radiation treatment shall be appropriately shielded. A certified physi- cist shall specify the type, location and amount of protection to be installed in accordance with final approved department layout and equipment selection. Radiation protection requirements shall be incorporated into the construction documents and comply with Chapter 31C and the requirements of California Radiation Control Regulations, California Code of Regulations, Title 17, Divi- sion 1, Chapter 5 and Subchapter 4.

1224.34.3.3 Room sizes. Rooms shall be sized as follows:

1. Cobalt rooms and linear accelerators shall be sized in accordance with equipment requirements and shall accommo- _date a gurney for litter borne patients. Layouts shall provide for preventing the escape of radioactive particles.
CRSC § 436.5. High relevance — show source text
DEPARTMENT OF HEALTH SERVICES

Authority: Sections 102, 208 and 25811.

Reference: Sections 102, 208 and 436.5.

ALL HEALING ARTS X-RAY INSTALLATIONS

Sec. 12-31C-101. All radiation shielding barriers in rooms and enclosures housing radiation machines shall comply with the mandatory standards and appendices in Report No. 35, “Dental X-RAY Protection”; Report 49, “Structural Shielding Design and Evaluation for Medical use of X-rays and Gamma Rays of Energies up to 10 MeV”; and Report No. 51, “Radiation Protection Design Guidelines for 0.1-100 MeV Particle Accelerator Facilities.” Published by the National Council on Radiation Protection and Measurements, 7910 Woodmont Avenue, Bethesda, Maryland 20814.

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12-71 AIR FILTERS

STANDARD 12-71-1

STATE FIRE MARSHAL

DESCRIPTION OF TEST APPARATUS, METHOD AND CLASSIFICATION REQUIREMENTS FOR AIR FILTERS

Sec. 12-71-100.

(a) Test apparatus.
1. The test duct, made of M.S. gage galvanized sheet metal reinforced with angle irons, is 21 inches square (13 548 mm [2] ) and 13 [1] / 2 feet (4114 mm) long.
2. One end of the duct is tapered to the discharge of a variable-speed blower and the other end is open to discharge. A metal filter frame is provided near the middle of the length of the duct to receive one 20 by 20 inches (508 mm by 508 mm) (nominal) filter unit. Two tightfitting doors, located to permit access to the filter frame, are each provided with a mica window to permit observation of both faces of the filter and conditions in the duct downstream from the filter.
3. Two 1-inch (25 mm) pipe elbows, about 18 inches (457 mm) from the base of the test filter, form gas burner outlets adjusted to provide yellow, wavering flames. The burners consume approximately 4 cubic feet (approximately 1,000 Btu/cubic feet) of gas per minute.
4. With the filter in place the air velocity is adjusted to approximately 200 linear feet per minute as measured at the discharge end of the duct by an Alnor Velometer Anemometer.
(b) Test method.
1. Filters are tested clean, that is, unused. The flames are applied for 3 minutes during which time observations are made of both faces of the filter as to the downstream travel of flame or sparks and the density, duration and character of the products of combustion.
CRSC § 1224.34 High relevance — show source text
1224.34 NUCLEAR MEDICINE.

1224.34.1 General. If nuclear medicine is provided, the following shall be provided:

1224.34.1.1 Radiation protection. A certified physicist shall specify the type, location and amount of radiation protection to be installed in accordance with final approved department layout and equipment selection. A physicist report shall also address dosing areas and circulation paths of dosed patients, including within multi-bay scanner rooms. Radiation protection require- ments shall be incorporated into the construction documents and comply with Chapter 31C and the requirements of California Radiation Control Regulations, California Code of Regulations, Title 17, Division 1, Chapter 5, and Subchapter 4.

1224.34.1.2 Nuclear medicine room. Shall be sized to accommodate the equipment and a gurney.

When provided, the following facilities shall meet the requirements below:

1224.34.1.2.1 Scintigraphy (Gamma Camera) Facilities. Shall include the following: 1. Scanner room. The scanner room shall provide a minimum clearance of 4 feet (1218 mm) at each side and the foot of the table.

2. Handwashing stations shall be provided throughout the gamma camera suite at locations of patient contact and at locations where radiopharmaceutical materials are handled, prepared or disposed of.

1224.34.1.2.2 Positron Emission Tomography (PET). Shall include the following: 1. Scanner room shall provide a minimum clearance of 4 feet (1218 mm) at each side and the foot of the table. Additional space shall be provided when PET is combined with CT and include compliance with Section 1224.18.3 and shielding requirements in Section 1224.34.1.1. 2. Cyclotron room. Where radiopharmaceuticals are prepared on-site, a cyclotron shall be provided. Cyclotron facilities shall be located in access-restricted areas. Shielding requirements for cyclotron facilities shall comply with Section 1224.34.1.1.

3. Control room. If a control room is required based on the physicist’s report, it shall be provided with a full direct view of the patient in the PET scanner. 4. Patient uptake/cool-down room. A shielded room with access to a dedicated patient toilet, to accommodate radioac- tive waste, and lavatory shall be provided. 5. Handwashing stations shall be provided throughout the PET suite at locations of patient contact and at locations where radiopharmaceutical materials are handled, prepared or disposed of. 6. Pre-procedure patient care and recovery area shall be provided to accommodate at least two stretchers. This area shall comply with Section 1224.34.2.6. 7. Imaging equipment room shall be provided in support of the equipment provided.

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INTERIOR ENVIRONMENT

8. Contaminated (hot) soiled holding shall be provided and operationally integrated to minimize incidental exposure to ionizing radiation.
CRSC § 12-16 High relevance — show source text
CALIFORNIA STANDARD FOR RESIDENTIAL EXCESS FLOW ACTUATED AUTOMATIC GAS SHUTOFF VALVES (SEE CCR TITLE 24, PART 5, CHAPTER 12) STANDARD 12-16-2

DIVISION OF THE STATE ARCHITECT

Authority: Sections 19200–19204, Health and Safety Code. Reference: Sections 19201.5 and 19202, Health and Safety Code.

DIVISION 1—CONSTRUCTION

SCOPE

Sec. 12-16-201. The American Society for Testing and Materials (ASTM) F2138-12(2017) Standard Specification for Excess Flow Valves for Natural Gas Service, and the American National Standards Institute (ANSI) Z21.93-2017/CSA 6.30-2017 Excess Flow Valves for Natural and LP Gas with Pressure up to 5 psig, shall be the applicable standards used by the Division of the State Architect for certification of these devices.

Sec. 12-16-201.1. Each installation of a customer-owned device that satisfies this standard shall be in accordance with the California Plumbing Code (CCR Title 24, Part 5).

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12-31C RADIATION SHIELDING STANDARDS

STANDARD 12-31C-1

DEPARTMENT OF HEALTH SERVICES

Authority: Sections 102, 208 and 25811.

Reference: Sections 102, 208 and 436.5.

ALL HEALING ARTS X-RAY INSTALLATIONS

Sec. 12-31C-101. All radiation shielding barriers in rooms and enclosures housing radiation machines shall comply with the mandatory standards and appendices in Report No. 35, “Dental X-RAY Protection”; Report 49, “Structural Shielding Design and Evaluation for Medical use of X-rays and Gamma Rays of Energies up to 10 MeV”; and Report No. 51, “Radiation Protection Design Guidelines for 0.1-100 MeV Particle Accelerator Facilities.” Published by the National Council on Radiation Protection and Measurements, 7910 Woodmont Avenue, Bethesda, Maryland 20814.

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12-71 AIR FILTERS

STANDARD 12-71-1

STATE FIRE MARSHAL

DESCRIPTION OF TEST APPARATUS, METHOD AND CLASSIFICATION REQUIREMENTS FOR AIR FILTERS

Sec. 12-71-100.

(a) Test apparatus.
1. The test duct, made of M.S. gage galvanized sheet metal reinforced with angle irons, is 21 inches square (13 548 mm [2] ) and 13 [1] / 2 feet (4114 mm) long.

CRSC § 12-16 High relevance — show source text

CHAPTER 12-16-1 ENGINEERING REGULATIONS—QUALITY

AND DESIGN OF THE MATERIALS OF

CONSTRUCTION . . . . . . . . . . . . . . . . . . . 101

CHAPTER 12-16-2 ENGINEERING REGULATIONS—QUALITY

AND DESIGN OF THE MATERIALS OF

CONSTRUCTION . . . . . . . . . . . . . . . . . . . 103

CHAPTER 12-31C RADIATION SHIELDING STANDARDS . . 105

CHAPTER 12-71 AIR FILTERS. . . . . . . . . . . . . . . . . . . . . . . 107

CHAPTER 12-72-1 PROTECTIVE SIGNALING SYSTEMS . . . 109

CHAPTER 12-72-2 PROTECTIVE SIGNALING SYSTEMS . . . 123

CHAPTER 12-72-3 PROTECTIVE SIGNALING SYSTEMS . . . 133

HISTORY NOTE APPENDIX . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

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PART 12 CROSS REFERENCE TABLE

(Cross reference table is nonregulatory, intended only as an aid to the code user.)

PART 12 STANDARD	SUBJECT	ADOPTING AGENCY	ASSOCIATED TITLE 24 BUILDING STANDARD
Chapter 12-3	Releasing systems for security bars in dwellings	SFM	Part 2, Sections 1031.2.1, 1031.6, 1032.7 Part 2.5, Sections R319.1.1 and R319.4.4 Part 9, Sections 1031.2.1, 1031.6, 1032.7 Appendix 4 Section 452.1.5 and Title 19 provisions 4.1, 4.2, 4.3, 4.4, 4.5, 4.6 reprinted in Part 9 Part 10, Section 505.4
Chapter 12-4A	Laboratory animal quarters standards	DPH	Part 2, Section 1236
Chapter 12-4-1	Stage and Platforms	SFM	Part 2, Sections 410.2.7, 410.2.7.1, 410.2.7.2 Part 9, Sections 105.6.51, 4809
Chapter 12-7-1	Fire-resistive standards.

CRSC § 31B-22 High relevance — show source text
3162B Anti-Entrapment Devices and Systems . . . . . . . . . . 31B-22

CHAPTER 31C RADIATION . . . . . . . . . . . . . . . . . . . . . . . . . .31C-1

3101C Scope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31C-3

3102C Radiation Shielding Barriers . . . . . . . . . . . . . . . . . . . . . 31C-3

3103C Medical Radiographic and Photofluorographic Installations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31C-3

3104C Medical Therapeutic X-Ray Installations. . . . . . . . . . 31C-3

CHAPTER 31D FOOD ESTABLISHMENTS. . . . . . . . . . . . . . .31D-1

3101D Scope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31D-3

3102D Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31D-3

3103D Buildings and Structures. . . . . . . . . . . . . . . . . . . . . . . . . 31D-3

CHAPTER 31E RESERVED. . . . . . . . . . . . . . . . . . . . . . . . . . .31E-1

CHAPTER 31F MARINE OIL TERMINALS . . . . . . . . . . . . . . .31F-1

3101F Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31F-3

3102F Audit and Inspection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31F-6

3103F Structural Loading Criteria . . . . . . . . . . . . . . . . . . . . . 31F-19

3104F Seismic Analysis and Structural Performance. . . . 31F-34

3105F Mooring and Berthing Analysis and Design . . . . . . 31F-48

3106F Geotechnical Hazards and Foundations . . . . . . . . . 31F-55
CRSC § 6.850 Medium relevance — show source text
850|6.850| |Water
source
electri-
cally
operated
centrifu-
gal|<75|≤0.6421
FL
≤0.5789
IPLV.IP|≤0.7316
FL
≤0.4632
IPLV.IP|54/445|≥4.640|≥3.680|≥2.680|NA|≥8.330|≥6.410|≥4.420|NA|AHRI
550/590| |Water
source
electri-
cally
operated
centrifu-
gal|<75|≤0.6421
FL
≤0.5789
IPLV.IP|≤0.7316
FL
≤0.4632
IPLV.IP|75/655|NA|NA|NA|≥3.550|NA|NA|NA|≥6.150|≥6.150| |Water
source
electri-
cally
operated
centrifu-
gal|≥75
and
<150|≤0.5895
FL
≤0.5474
IPLV.IP|≤0.6684
FL
≤0.4211
IPLV.IP|54/445|≥4.640|≥3.680|≥2.680|NA|≥8.330|≥6.410|≥4.420|NA|NA| |Water
source
electri-
cally
operated
centrifu-
gal|≥75
and
<150|≤0.5895
FL
≤0.5474
IPLV.IP|≤0.6684
FL
≤0.4211
IPLV.IP|75/655|NA|NA|NA|≥3.550|NA|NA|NA|≥6.150|≥6.150| |Water
source
electri-
cally
operated
centrifu-
gal|≥150
and
<300|≤0.5895
FL
≤0.5263
IPLV.IP|≤0.6263
FL
≤0.4105
IPLV.IP|54/445|≥4.640|≥3.680|≥2.680|NA|≥8.330|≥6.410|≥4.420|NA|NA| |Water
source
electri-
cally
operated
centrifu-
gal|≥150
and
<300|≤0.5895
FL
≤0.5263
IPLV.IP|≤0.6263
FL
≤0.4105
IPLV.IP|75/655|NA|NA|NA|≥3.550|NA|NA|NA|≥6.150|≥6.150|
CRSC § 31B-20 Medium relevance — show source text
3154B Reserved. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31B-20

3155B Reserved. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31B-20

3156B Reserved. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31B-20

3157B Reserved. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31B-21

3158B Reserved. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31B-21

3159B Reserved. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31B-21

DIVISION II – PUBLIC SWIMMING POOLS. . . . . . . . . . . . . . .31B-21

3160B Ground Fault Circuit Interrupters. . . . . . . . . . . . . . . . 31B-21

3161B Wading Pools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31B-21

3162B Anti-Entrapment Devices and Systems . . . . . . . . . . 31B-22

CHAPTER 31C RADIATION . . . . . . . . . . . . . . . . . . . . . . . . . .31C-1

3101C Scope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31C-3

3102C Radiation Shielding Barriers . . . . . . . . . . . . . . . . . . . . . 31C-3

3103C Medical Radiographic and Photofluorographic Installations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31C-3

3104C Medical Therapeutic X-Ray Installations. . . . . . . . . . 31C-3

CHAPTER 31D FOOD ESTABLISHMENTS. . . . . . . . . . . . . . .31D-1

3101D Scope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31D-3
CRSC § 12-10 Medium relevance — show source text
CHAPTER 12-10-1 EXITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

CHAPTER 12-10-2 EXITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

CHAPTER 12-10-3 EXITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

CHAPTERS 12-11A AND 12-11B

BUILDING AND FACILITY ACCESS

SPECIFICATIONS. . . . . . . . . . . . . . . . . . . . 85

CHAPTER 12-12 RESERVED . . . . . . . . . . . . . . . . . . . . . . . . . 87

CHAPTER 12-13 STANDARDS FOR INSULATING

MATERIAL. . . . . . . . . . . . . . . . . . . . . . . . . . 89

CHAPTER 12-16-1 ENGINEERING REGULATIONS—QUALITY

AND DESIGN OF THE MATERIALS OF

CONSTRUCTION . . . . . . . . . . . . . . . . . . . 101

CHAPTER 12-16-2 ENGINEERING REGULATIONS—QUALITY

AND DESIGN OF THE MATERIALS OF

CONSTRUCTION . . . . . . . . . . . . . . . . . . . 103

CHAPTER 12-31C RADIATION SHIELDING STANDARDS . . 105

CHAPTER 12-71 AIR FILTERS. . . . . . . . . . . . . . . . . . . . . . . 107

CHAPTER 12-72-1 PROTECTIVE SIGNALING SYSTEMS . . . 109

CHAPTER 12-72-2 PROTECTIVE SIGNALING SYSTEMS . . . 123

CHAPTER 12-72-3 PROTECTIVE SIGNALING SYSTEMS . . . 133

HISTORY NOTE APPENDIX . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

2025 CALIFORNIA REFERENCED STANDARDS CODE vii

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

viii 2025 CALIFORNIA REFERENCED STANDARDS CODE

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

PART 12 CROSS REFERENCE TABLE

(Cross reference table is nonregulatory, intended only as an aid to the code user.)

Frequently asked questions

Who sets the actual shielding thickness and calculations that the code requires?

The CRSC requires that designers use the mandatory NCRP reports listed in § 12-31C-101; the numerical thicknesses and calculations come from those NCRP reports and from the project physicist’s calculations based on those reports.

Can a local building official approve an alternate shielding method?

No — variances or exceptions to the standards referenced in § 12-31C-101 may only be granted by the Department of Health Services as described in the CBC cross-reference.

Does § 12-31C-101 itself contain shielding formulas or tables?

No. § 12-31C-101 makes NCRP Reports 35, 49 and 51 mandatory references; the CRSC text does not reproduce their technical tables or formulas.

Who should prepare the shielding report for permit submittal?

A qualified/certified radiation physicist should prepare the shielding evaluation and specification for incorporation into construction documents; the CBC requires a physicist’s specification for many medical radiation rooms.

Which NCRP report do I use for a 25 MeV cyclotron?

Use NCRP Report No. 51, which covers 0.1–100 MeV particle accelerator facilities, per § 12-31C-101.

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How must radiation shielding barriers demonstrate compliance?

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