CRSC · California Referenced Standards Code

What interlocks and radiation‑reduction requirements apply above 150 kVp?

If an x‑ray therapy unit operates above 150 kVp, California’s CRSC requires interlocks so opening any treatment‑room door either stops the machine or reduces radiation to a very low level (≤2 mR/hr average and ≤10 mR/hr max measured at 1 meter); the machine may only be restarted from the control panel, and the operator must be in a protective booth or adjacent room.

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Last reviewed: July 6, 2026

What the code requires — 2–4 sentences

For any therapeutic x‑ray equipment operating above 150 kVp, the room must have interlocks so that opening any room door either causes the machine to shut off automatically or reduces the radiation to an average of not more than 2 milliroentgens per hour and a maximum of 10 milliroentgens per hour measured at one meter from the target; after such shutoff/reduction the unit may be restored to full operation only from the control panel. This requirement is the CRSC controlling rule in § 3104C.3.

The single most important rule: if an access door opens during operation of equipment above 150 kVp, either the beam must stop automatically or the radiation in the room must drop to ≤2 mR/hr (average) and never exceed 10 mR/hr at 1 m from the target; the machine can only be restarted from the control panel.

Requirements in detail

Scope and trigger

Applies to equipment operating above 150 kVp (threshold). § 3104C.3 is the controlling text.
The interlock must be connected to any door of the treatment room so that opening the door triggers the required action (shutoff or radiation reduction).

Required interlock actions

Two acceptable outcomes when a door opens:
- The machine will shut off automatically, or
- The radiation level within the room is reduced to meet both the average and maximum limits specified below. Restoration to full operation must be possible only from the control panel.

Radiation‑reduction limits and measurement points

Average limit: not more than 2 milliroentgens per hour (2 mR/hr).
Maximum allowable spike: not more than 10 milliroentgens per hour (10 mR/hr).
Measurement location: at a distance of one meter in any direction from the target. These limits are specified in § 3104C.3.

Control station and viewing

The control station must be located within a protective booth or in an adjacent room (control‑location requirement in § 3104C.3).
For equipment operating above 50 kVp, the control station shielding and viewing requirements (window attenuation equal to the adjacent barrier, mirror or CCTV) in § 3104C.2 also apply.

Access doors and emergency access

If large power‑driven doors are the only access, at least one door must have an auxiliary means for opening in case of power failure or mechanical breakdown (see § 3104C.4).

Additional signals for very‑high‑energy equipment

For equipment capable of operating above 500 kVp, a flashing red warning light energized only when the useful beam is on is required adjacent to the entrance(s) (see § 3104C.5).

Quick reference table (decision‑relevant values)

Decision dimension	Value / threshold	Why it matters	Code Reference
Equipment energy	Above 150 kVp	Triggers interlock / reduction requirement	§ 3104C.3
Door open action	Automatic shutoff OR radiation reduced	Safety control when room access opens	§ 3104C.3
Radiation average limit	≤ 2 milliroentgens/hour at 1 m	Prescribed reduced operating level	§ 3104C.3
Radiation maximum spike	≤ 10 milliroentgens/hour at 1 m	Absolute maximum during reduction	§ 3104C.3
Restart control	Only from control panel	Prevents bypassing interlock at door	§ 3104C.3
Control station location	Protective booth or adjacent room	Operator protection & visibility	§ 3104C.3
Visibility / window attenuation	Window = attenuation of adjacent barrier or mirror/CCTV	Operator must see patient without leaving shield	§ 3104C.2
Emergency door opening	Auxiliary opener required for large power doors	Means of egress if power fails	§ 3104C.4
High‑energy warning light	Flashing red light when beam on for > 500 kVp equipment	Additional conspicuity for very high energy units	§ 3104C.5

Exceptions & special cases

The CRSC text requires “shutoff or reduction to the stated limits” but does not prescribe the technical design of the interlock circuitry, specific detectors, or timing/averaging interval for the “average” measurement. The retrieval does not include measurement protocol details; consult regulatory health agencies, equipment manufacturers, or NCRP/NEMA device standards for test methods.
If a facility chooses the “reduction” option instead of full shutoff, both the average and maximum limits must be met at 1 m from the target in any direction; both criteria must be satisfied simultaneously.
For rooms with large power‑driven doors, install the auxiliary opener required by § 3104C.4 so staff/patients can exit during power loss.
For units capable of >500 kVp, the flashing red warning light requirement in § 3104C.5 is mandatory in addition to the interlock/reduction requirement when applicable.

Common mistakes

Assuming interlocks only need to act on the primary entrance; the code ties the interlock to “any door of the treatment room.” § 3104C.3 requires coverage of all doors.
Measuring radiation at the wrong location or distance — the limits are at one meter from the target. Do not use room perimeter readings or measurements at different distances to claim compliance. § 3104C.3.
Confusing average vs maximum limits. Both the ≤ 2 mR/hr average and the ≤ 10 mR/hr maximum must be satisfied. § 3104C.3.
Restarting the machine at the door or in the room after a door‑open event — the code requires restoration only from the control panel. § 3104C.3.
Omitting an auxiliary door opener where large power doors are the only access, contrary to § 3104C.4.

Worked example

Scenario: A clinic installs a therapeutic x‑ray unit that operates at 250 kVp. The design team must meet CRSC interlock rules.

Step 1 — Apply the threshold: 250 kVp is above 150 kVp, so § 3104C.3 applies.

Step 2 — Choose interlock strategy:

Option A — configure the room so any door opening immediately shuts the machine off. This is fully compliant per § 3104C.3.
Option B — configure the system to reduce output when any door opens. To comply, verify (a) the average radiation at 1 m from the target is ≤ 2 mR/hr, and (b) the instantaneous/maximum reading does not exceed 10 mR/hr at the same 1 m point.

Concrete numbers (Option B): After a door opens the detector at 1 m reads a short spike to 8 mR/hr, and over the following monitoring interval the averaged reading is 1.6 mR/hr. Both numbers meet the CRSC criteria (1.6 ≤ 2 mR/hr average and 8 ≤ 10 mR/hr max), so the design is compliant with § 3104C.3, provided the restart control is only at the control panel. Note: choose a test method/averaging interval from accepted radiological test standards because the CRSC text does not specify averaging protocol.

Related provisions

§ 3104C.1 — Primary protective barrier requirements for areas that can be struck by the useful beam.
§ 3104C.2 — Requirements for equipment operating above 50 kVp (control station shielding/visibility).
§ 3104C.4 — Auxiliary means for opening at least one door where large power doors are the only access.
§ 3104C.5 — Flashing red warning light required when beam on for equipment capable of above 500 kVp.
Sections 3101C–3103C — Definitions (e.g., primary protective barrier, stray radiation, useful beam) and radiographic room requirements that provide context for shielding and operator protection.

Code references

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

CRSC § 3103C.1 High relevance — show source text
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.

3104C.3 Equipment operating above 150 kVp. Equipment operating above 150 kVp shall conform to the following: 1. The treatment room shall be provided with interlocks so that when any door of the treatment room is opened, either the machine will shut off automatically or the radiation level within the room will be reduced to an average of not more than 2 milliroentgens per hour and a maximum of 10 milliroentgens per hour at a distance of one meter in any direction from the target. After such shutoff or reduction in output, it shall be possible to restore the machine to full operation only from the control panel. 2. The control station shall be within a protective booth or in an adjacent room.

3104C.4 A minimum of one door shall be provided with an auxiliary means for being opened in case of power failure or mechanical breakdown, where large power-driven doors offer the only access to the room.

3104C.5 A flashing red warning signal light energized only when the useful beam is on shall be located adjacent to the entrance(s) to a therapy room with equipment capable of operating above 500 kVp.

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CALIFORNIA BUILDING CODE – MATRIX ADOPTION TABLE

CHAPTER 31D – FOOD ESTABLISHMENTS

(Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)
CRSC § 516.2.9 High relevance — show source text
516.2.9 Listing Evaluation. Listing evaluation shall include the following:

(1) Capture and containment of vapors at published and labeled airflows.

(2) Grease discharge at the exhaust outlet of the system not to exceed an average of 2.9 E-09 (oz/in [3] ) (5.0 E-06 kg/m [3] ) of exhausted air sampled from that equipment at maximum amount of product that is capable of

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EXHAUST SYSTEMS

being processed over a continuous 8 hour test with the system operating at its minimum listed airflow.

(3) Listing and labeling of clearance to combustibles from all sides, top, and bottom.

(4) Electrical connection in the field in accordance with the California Electrical Code .

(5) Interlocks on all removable components that lie in the path of airflow within the unit to ensure that they are in place during operation of the cooking appliance. {NFPA 96:14.2.12}

516.3 Interlocks. The recirculating system shall be provided with interlocks of all critical components and operations as indicated in Section 516.3.1 through Section 516.3.3.1 such that, if any of these interlocks are interrupted, the cooking appliance will not be able to operate. [NFPA 96:14.3.1]

516.3.1 Airflow Sections. All closure panels encompassing airflow sections shall have interlocks to ensure that the panels are in place and fully sealed. [NFPA 96:14.3.2]

516.3.2 Filter Component. Each filter component (grease and odor) shall have an interlock to prove the component is in place. [NFPA 96:14.3.3]

516.3.3 ESP Interlocks. Each ESP shall have a sensor to prove its performance is as designed, with no interruption of the power to exceed 2 minutes. [NFPA 96:14.3.4.1]

516.3.3.1 Manual Reset. The sensor shall be a manual reset device or circuit. [NFPA 96:14.3.4.2]

516.3.4 Airflow Switch or Transducer. An airflow switch or transducer shall be provided after the last filter component to ensure that a minimum airflow is maintained. The airflow switch or transducer shall open the interlock circuit when the airflow falls 25 percent below the system’s normal operating flow or 10 percent below its listed minimum rating, whichever is lower. The airflow switch or transducer shall be a manual reset device or circuit. [NFPA 96:14.3.5.1 – 14.3.5.3]

516.4 Location and Application Restrictions. The location of recirculating systems shall be approved by the Authority Having Jurisdiction. Items to be reviewed in the fire risk assessment shall include, but not be limited to, life safety, combustibility of surroundings, proximity to air vents, and total fuel load. [NFPA 96:14.4.1 – 14.4.2]
CRSC § 516.2.2 High relevance — show source text
516.2.2 Recirculation. Recirculating systems shall be listed with a testing laboratory in accordance with UL 710B or equivalent. [NFPA 96:14.2.4]

516.2.3 Protection. Cooking appliances that require protection and that are under a recirculating hood shall be protected by either the integral fire protection system in accordance with UL 710B or a system in accordance with Section 513.0. [NFPA 96:14.2.4.2]

516.2.4 Maximum Limits. A recirculating system shall not use cooking equipment that exceeds that recirculating system’s labeled maximum limits for that type of equipment, stated in maximum energy input, maximum cooking temperature, and maximum square area of cooking surface or cubic volume of cooking cavity. [NFPA 96:14.2.6]

516.2.5 Label. The listing label shall show the type(s) of cooking equipment tested and the maximum limits specified in Section 516.2.4. [NFPA 96:14.2.7]

516.2.6 Fire Damper. A fire-actuated damper shall be installed at the exhaust outlet of the system. [NFPA 96:14.2.8] The actuation device for the fire damper shall have a maximum temperature rating of 375°F (191°C).

[NFPA 96:14.2.10]

516.2.7 Installation of Electrical Wiring. No electrical wiring shall be installed in the interior sections of the hood plenum that is capable of becoming exposed to grease.

Exception: As permitted by the California Electrical Code . 516.2.8 Power Supply. The power supply of any electrostatic precipitator (ESP) shall be of the “cold spark,” ferroresonant type in which the voltage falls off as the current draw of a short increases. [NFPA 96:14.2.11]

516.2.9 Listing Evaluation. Listing evaluation shall include the following:

(1) Capture and containment of vapors at published and labeled airflows.

(2) Grease discharge at the exhaust outlet of the system not to exceed an average of 2.9 E-09 (oz/in [3] ) (5.0 E-06 kg/m [3] ) of exhausted air sampled from that equipment at maximum amount of product that is capable of

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EXHAUST SYSTEMS

being processed over a continuous 8 hour test with the system operating at its minimum listed airflow.

(3) Listing and labeling of clearance to combustibles from all sides, top, and bottom.

(4) Electrical connection in the field in accordance with the California Electrical Code .

(5) Interlocks on all removable components that lie in the path of airflow within the unit to ensure that they are in place during operation of the cooking appliance. {NFPA 96:14.2.12}

516.3 Interlocks. The recirculating system shall be provided with interlocks of all critical components and operations as indicated in Section 516.3.1 through Section 516.3.3.1 such that, if any of these interlocks are interrupted, the cooking appliance will not be able to operate. [NFPA 96:14.3.1]
CRSC § 120.7 High relevance — show source text
7(b)3, 120.7(b)4, 120.7(b)6, 120.7(c)1, 120.7(c)2, Table 140.3-A, 140.3(a)1, 140.3(a)2, 140.3(a)3, 140.3(a)4, 140.3(a)5, 140.3(a)6, 140.3(a)7, Table 140.3-B, Table 140.3-C, Table 140.3-D, Table 141.0-A, Table 141.0-B, Table 141.0-C, 141.0(b)2B, Table 141.0-E, 141.0(b)3, 150.0(a), 150.0(c), 150.0(d), 150.0(q), 150.1(c)1, 150.1(c)3, Table 150.1-A, 150.1(c)5, 150.1(c)8, 150.2(b)1A, 150.2(b)1B, 150.2(b)1N, 150.2(b)2, Table 150.2-D, 160.1(a), 160.1(b), 160.1(c), 160.1(e), 160.3(c)2H, 170.2(a)2, 170.2(a)4, 170.2(a)5, Table 170.2-A, 180.1(a)1, 180.2(a), 180.2(b)1, 2, 180.2(c) Ultrasonic Radiation 110.9(b)6 Ultrasonic Sensor 140.6(a)3, 170.2(e)2 Ultrasound Maximum Decibel Values

Table 110.9-A Ultraviolet Light 150.0(f) Ultraviolet Radiation 110.8(g)2 Unconditioned Agricultural building 140.6(a)3P Area 140.6(b)1, 170.2(e)3 Crawlspace 160.3(c)2, 180.2(b)2 Space 120.4(a), 120.4(g), 120.7(a), 120.7(b), 120.7(c), 140.3(a)3, 140.3(a)7, 140.3(c), 140.6(b)3, 141.0(b)1A, 141.0(b)1B, 141.0(b)1C, 150.0(a), 150.0(c), 150.0(d), 150.0(k)1, 150.0(m)1, 150.0(q), 150.1(c)5, 150.2(a)1A, 150.2(b)1D, 160.1(a), 160.1(b), 160.1(c), 160.1(e), 160.3(b)5, 160.3(c), 170.2(a)4, 170.2(e)3, 180.2(a), 180.2(b)2 Undershelf Lighting 150.0(k)2, 160.5(a) Underwriters Laboratories (UL) 110.2(f), 120.4(b)1, 2, 120.4(c), 130.0(c), 150.0(m)1, 150.0(m)2, 150.

CRSC § 1004.4 High relevance — show source text

[Equation 1004.4(1)]

Vt (forced-type) = [(0.00041] [t] [ - 0.0466) ] [V][s]

(

P P a a

Pf Po )

[Equation 1004.4(2)]

Vt (diaphragm-type) = [(0.00041] [t] [ - 0.0466) ] [V][s]

– [P][f]

[1]

( Po )

Where:

Vt = Minimum volume of expansion tank, gallons. Vs = Volume of system, not including expansion tank, gallons.

t = Average operating temperature, °F.

Pa = Atmospheric pressure, pounds per square inch. Pf = Fill pressure, pounds per square inch. Po = Maximum operating pressure, pounds per square inch.

For SI units: 1 gallon = 3.785 L

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BOILERS AND PRESSURE VESSELS

TABLE 1004.4(1) EXPANSION TANK CAPACITIES FOR GRAVITY HOT WATER SYSTEMS [1]

INSTALLED EQUIVALENT DIRECT RADIATION2 (square feet)	TANK CAPACITY (gallons)
Up to 350	18
Up to 450	21
Up to 650	24
Up to 900	30
Up to 1100	35
Up to 1400	40
Up to 1600	2 to 30
Up to 1800	2 to 30
Up to 2000	2 to 35
Up to 2400	2 to 40

For SI units: 1 gallon = 3.785 L, 1 square foot = 0.0929 m [2]

Notes: 1 Based on a two-pipe system with an average operating water temperature of 170°F (77°C), using cast-iron column radiation with a heat emission rate of 150 British thermal units per square foot hour [Btu/(ft [2] - h)] (473 W/m [2] ) equivalent direct radiation. 2 For systems that exceed 2400 square feet (222.9 m 2 ) of installed equivalent direct water radiation, the required capacity of the cushion tank shall be increased on the basis of 1 gallon (4 L) tank capacity per 33 square feet (3.1 m [2] ) of additional equivalent direct radiation.

TABLE 1004.4(2) EXPANSION TANK CAPACITIES FOR FORCED HOT WATER SYSTEMS [1]

California Referenced Standards Code Medium relevance — show source text
3/8″
main reinforcement bars at 57/8″ pitch
with7/8″ concrete cover;3/8″ main rein-
forcement bars at 41/2″ pitch
perpendicular with1/2″ concrete cover;
13′1″ span restrained.|195 psf|4 hrs|||7|1, 7|4| |F/C-4-RC-7|4″|4″ (5025 psi) concrete deck;1/4″ reinforce-
ment bars at 71/2″ pitch with3/4″ cover;3/8″
main reinforcement bars at 33/4″ pitch
perpendicular with1/2″ cover; 13′1″ span
restrained.|140 psf|1 hr
16 min|||7|1, 2|11/4| |F/C-4-RC-8|4″|4″ thick (4905 psi) deck;1/4″ reinforce-
ment bars at 71/2″ pitch with7/8″ cover;3/8″
main reinforcement bars at 33/4″ pitch
perpendicular with1/2″ cover; 13′1″ span
restrained.|100 psf|1 hr
23 min|||7|1, 2|11/3| |F/C-4-RC-9|4″|4″ deep (4370 psi);1/4″ reinforcement bars
at 6″ pitch with3/4″ cover;1/4″ main rein-
forcement bars at 4″ pitch perpendicular
with1/2″ cover; 13′1″ span restrained.|150 psf|2 hrs|||7|1, 3|2| |F/C-4-RC-10|4″|4″ thick (5140 psi) deck;1/4″ reinforce-
ment bars at 71/2″ pitch with7/8″ cover;3/8″
main reinforcement bars at 33/4″ pitch
perpendicular with1/2″ cover; 13′1″ span
restrained.|140 psf|1 hr
16 min|||7|1, 5|11/4| |F/C-4-RC-11|4″|4″ thick (4000 psi) concrete deck;
3″ × 11/2″ × 4 lbs R.S.J.; 2′6″ C.R.S.; flush
with top surface; 4″ × 6″ x 13 SWG mesh
reinforcement 1″ from bottom of slab; 6′6″
span restrained.|150 psf|2 hrs|||7|1, 3|2| |F/C-4-RC-12|4″|4″ deep (2380 psi) concrete deck;
3″ × 11/2″ × 4 lbs R.S.J.; 2′6″ C.R.S.
California Referenced Standards Code Medium relevance — show source text
|100 psf|1 hr
23 min|||7|1, 2|11/3| |F/C-4-RC-9|4″|4″ deep (4370 psi);1/4″ reinforcement bars
at 6″ pitch with3/4″ cover;1/4″ main rein-
forcement bars at 4″ pitch perpendicular
with1/2″ cover; 13′1″ span restrained.|150 psf|2 hrs|||7|1, 3|2| |F/C-4-RC-10|4″|4″ thick (5140 psi) deck;1/4″ reinforce-
ment bars at 71/2″ pitch with7/8″ cover;3/8″
main reinforcement bars at 33/4″ pitch
perpendicular with1/2″ cover; 13′1″ span
restrained.|140 psf|1 hr
16 min|||7|1, 5|11/4| |F/C-4-RC-11|4″|4″ thick (4000 psi) concrete deck;
3″ × 11/2″ × 4 lbs R.S.J.; 2′6″ C.R.S.; flush
with top surface; 4″ × 6″ x 13 SWG mesh
reinforcement 1″ from bottom of slab; 6′6″
span restrained.|150 psf|2 hrs|||7|1, 3|2| |F/C-4-RC-12|4″|4″ deep (2380 psi) concrete deck;
3″ × 11/2″ × 4 lbs R.S.J.; 2′6″ C.R.S.; flush
with top surface; 4″ × 6″ x 13 SWG mesh
reinforcement 1″ from bottom surface;
6′6″ span restrained.|150 psf|1 hr
3 min|||7|1, 2|1| |F/C-4-RC-13|41/2″|41/2″ thick (5200 psi) deck;1/4″ reinforce-
ment bars at 71/4″ pitch with7/8″ cover;3/8″
main reinforcement bars at 33/4″ pitch
perpendicular with1/2″ cover; 13′1″ span
restrained.|140 psf|2 hrs|||7|1, 3|2| |F/C-4-RC-14|41/2″|41/2″ deep (2525 psi) concrete deck;1/4″
reinforcement bars at 71/2″ pitch with7/8″
cover;3/8″ main reinforcement bars at
33/8″ pitch perpendicular with1/2″ cover;
13′1″ span restrained.|150 psf|42 min|||7|1, 5|2/3| |F/C-4-RC-15|41/2″|41/2″ deep (4830 psi) concrete deck;
11/2″ × No.

CRSC § 1909.3.3 Medium relevance — show source text

1909.3.3 ACI 318, Chapter 14. Plain concrete is not permitted.

1909.3.4 ACI 318, Section 18.10.6.5. Modify ACI 318, Section 18.10.6.5 by adding the following:

Where boundary members are not required by ACI 318 Section 18.10.6.2 or 18.10.6.3, minimum reinforcement parallel to the edges of all structural walls and the boundaries of all openings shall consist of twice the cross-sectional area of the minimum shear reinforce- ment required per lineal foot of wall. Horizontal extent of boundary element shall be per ACI 318 Section 18.10.6.4 (a), (b) and (c).

1909.3.5 ACI 318, Section 18.12.6. Add Section 18.12.6.2 to ACI 318 as follows:

Collector and boundary elements in topping slabs placed over precast floor and roof elements shall not be less than 3 inches (76 mm) or 6 d b thick, where d b is the diameter of the largest reinforcement in the topping slab.

1909.3.6 ACI 318, Table 21.2.2. Replace Table 21.2.2 as follows:

TABLE 21.2.2 STRENGTH REDUCTION FACTOR φ FOR MOMENT, AXIAL FORCE, OR COMBINED MOMENT AND AXIAL FORCE	Col2	Col3	Col4	Col5	Col6
NET TENSILE STRAINεt	CLASSIFICATION	φ	φ	φ	φ
NET TENSILE STRAINεt	CLASSIFICATION	Type of transverse reinforcement	Type of transverse reinforcement	Type of transverse reinforcement	Type of transverse reinforcement
NET TENSILE STRAINεt	CLASSIFICATION	Spirals conforming to 25.7.3	Spirals conforming to 25.7.3	Other	Other
εt ≤ εty	Compression-controlled	0.75	(a)	0.65	(b)
εty < εt < (εty + 0.003)	Transition1,2	0.75 0.15 ε_t_ ε_ty_ – ε_t_ ε_ty_ – ---------------- + *	(c)	0.65 0.25 ε_t_ ε_ty_ – ε_t_ ε_ty_ – ---------------- + *	(d)
εt ≥ (εty + 0.003)	Tension-controlled_3_	0.9	(e)	0.9	(f)
1. For sections classified as transition, it shall be permitted to useφ corresponding to compression-controlled sections. 2. ε_t_ * is the greater of net tensile strain calculated for Pn = 0.1Agf c′_ and (ε_ty + 0.003). _3.

CRSC § 3104C.4 Medium relevance — show source text

3104C.4 A minimum of one door shall be provided with an auxiliary means for being opened in case of power failure or mechanical breakdown, where large power-driven doors offer the only access to the room.

3104C.5 A flashing red warning signal light energized only when the useful beam is on shall be located adjacent to the entrance(s) to a therapy room with equipment capable of operating above 500 kVp.

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CALIFORNIA BUILDING CODE – MATRIX ADOPTION TABLE

CHAPTER 31D – FOOD ESTABLISHMENTS

(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	X									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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31D [DPH] FOOD ESTABLISHMENTS

SECTION 3101D—SCOPE

The provisions of this chapter shall apply to the construction of commissaries serving mobile food preparation units.

SECTION 3102D—DEFINITION

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

CRSC § 3.785 Medium relevance — show source text

INSTALLED EQUIVALENT DIRECT RADIATION2 (square feet)	TANK CAPACITY (gallons)
Up to 350	18
Up to 450	21
Up to 650	24
Up to 900	30
Up to 1100	35
Up to 1400	40
Up to 1600	2 to 30
Up to 1800	2 to 30
Up to 2000	2 to 35
Up to 2400	2 to 40

For SI units: 1 gallon = 3.785 L, 1 square foot = 0.0929 m [2]

Notes: 1 Based on a two-pipe system with an average operating water temperature of 170°F (77°C), using cast-iron column radiation with a heat emission rate of 150 British thermal units per square foot hour [Btu/(ft [2] - h)] (473 W/m [2] ) equivalent direct radiation. 2 For systems that exceed 2400 square feet (222.9 m 2 ) of installed equivalent direct water radiation, the required capacity of the cushion tank shall be increased on the basis of 1 gallon (4 L) tank capacity per 33 square feet (3.1 m [2] ) of additional equivalent direct radiation.

TABLE 1004.4(2) EXPANSION TANK CAPACITIES FOR FORCED HOT WATER SYSTEMS [1]

SYSTEM VOLUME2 (gallons)	TANK CAPACITY DIAPHRAGM TYPE (gallons)	TANK CAPACITY NON- DIAPHRAGM TYPE (gallons)
100	9	15
200	17	30
300	25	45
400	33	60
500	42	75
1000	83	150
2000	165	300

For SI units: 1 gallon = 3.785 L

Notes: 1 Based on an average operating water temperature of 195°F (91°C), a fill pressure of 12 psig (83 kPa), and an operating pressure of not more than 30 psig (207 kPa). 2 Includes volume of water in boiler, radiation, and piping, not including expansion tank.

1005.0 Safety or Relief Valve Discharge.

1005.1 General. Pressurized vessels or boilers shall be provided with overpressure protection by means of a listed pressure relief valve installed in accordance with the manufacturer’s

installation instructions.

1005.2 Discharge Piping. The discharge piping serving a temperature relief valve, pressure relief valve, or combination of both shall have no valves, obstructions, or means of isolation and provided with the following:

(1) Not less than the size of the valve outlet and shall discharge full size to the flood level of the area receiving the discharge and pointing down.

(2) Materials shall be rated at not less than the operating temperature of the system and approved for such use or shall comply with ASME A112.4.1.

CRSC § 2.95 Medium relevance — show source text
00|2.95|2.20|1.45|3.00|2.35|1.25|DR| |Cold-formed steel framing
(minimum penetration of steel
thickness plus 3 threads)|#8 screw into 33 mil steel or
thicker|8|3.00|2.55|1.60|0.60|3.00|1.80|DR|DR| |Cold-formed steel framing
(minimum penetration of steel
thickness plus 3 threads)|#8 screw into 33 mil steel or
thicker|12|3.00|1.80|DR|DR|3.00|0.65|DR|DR| |Cold-formed steel framing
(minimum penetration of steel
thickness plus 3 threads)|#10 screw into 33 mil steel|6|4.00|3.50|2.70|1.95|4.00|2.90|1.70|0.55| |Cold-formed steel framing
(minimum penetration of steel
thickness plus 3 threads)|#10 screw into 33 mil steel|8|4.00|3.10|2.05|1.00|4.00|2.25|0.70|DR| |Cold-formed steel framing
(minimum penetration of steel
thickness plus 3 threads)|#10 screw into 33 mil steel|12|4.00|2.25|0.70|DR|3.70|1.05|DR|DR| |Cold-formed steel framing
(minimum penetration of steel
thickness plus 3 threads)|#10 screw into 43 mil steel or
thicker|6|4.00|4.00|4.00|3.60|4.00|4.00|3.45|2.70| |Cold-formed steel framing
(minimum penetration of steel
thickness plus 3 threads)|#10 screw into 43 mil steel or
thicker|8|4.00|4.00|3.70|3.00|4.00|3.85|2.80|1.80| |Cold-formed steel framing
(minimum penetration of steel
thickness plus 3 threads)|#10 screw into 43 mil steel or
thicker|12|4.00|3.85|2.80|1.80|4.00|3.05|1.50|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. Cold-formed steel framing shall be minimum 33 ksi steel for 33 mil and 43 mil steel and 50 ksi steel for 54 mil steel or thicker.
b. Screws shall comply with the requirements of AISI S240.
c. Foam sheathing shall have a minimum compressive strength of 15 pounds per square inch in accordance with ASTM C578 or ASTM C1289.|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. Cold-formed steel framing shall be minimum 33 ksi steel for 33 mil and 43 mil steel and 50 ksi steel for 54 mil steel or thicker.
b.
CRSC § 1.11. Medium 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.

2025 CALIFORNIA BUILDING CODE 31C-1

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

31C-2 2025 CALIFORNIA BUILDING CODE

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

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.

Frequently asked questions

Who decides whether to implement shutoff vs. reduction?

The code allows either approach; the design team (owner, radiation safety officer, and AHJ) typically decide which option to implement. Whichever is chosen must meet the limits and restart rules in § 3104C.3.

Is the averaging method for the “average of not more than 2 mR/hr” specified?

No — § 3104C.3 sets the average limit but does not specify measurement interval or averaging method. Use recognized dosimetry/test standards or consult the Authority Having Jurisdiction (AHJ) and radiation safety experts for test procedures.

Does the flashing red light requirement apply at 200 kVp?

No. The flashing red warning light is required only for equipment capable of operating above 500 kVp as stated in § 3104C.5.

Do interlocks have to cover all doors?

Yes — § 3104C.3 specifies interlocks so that when any door of the treatment room is opened the shutoff or reduction requirement is triggered.

What if the facility has large power‑driven doors?

Install an auxiliary means to open at least one door in case of power failure or mechanical breakdown as required by § 3104C.4.

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California Referenced Standards Code