The storage and use of highly toxic and toxic materials shall comply with this chapter. Compressed gases shall also comply with Chapter 53.
Exceptions:
- Display and storage in Group M and storage in Group S occupancies complying with Section 5003.11.
Conditions involving pesticides or agricultural products as follows:
- 2.1. Application and release of pesticide, agricultural products and materials intended for use in weed abatement, erosion control, soil amendment or similar applications when applied in accordance with the manufacturer's instruction and label directions.
- 2.2. Transportation of pesticides in compliance with the Federal Hazardous Materials Transportation Act and regulations thereunder.
- 2.3. Storage in dwellings or private garages of pesticides registered by the U.S. Environmental Protection Agency to be utilized in and around the home, garden, pool, spa and patio.
Permits shall be required as set forth in Section 105.6.
The following terms are defined in Chapter 2:
Mechanical exhaust ventilation shall be provided for highly toxic and toxic liquids used in open systems in accordance with Section 5005.2.1.1.
Exception: Liquids that do not generate highly toxic or toxic fumes, mists or vapors.
Mechanical exhaust ventilation shall be provided for highly toxic and toxic liquids used in closed systems in accordance with Section 5005.2.2.1.
Exception: Liquids that do not generate highly toxic or toxic fumes, mists or vapors.
Toxic and highly toxic compressed gases shall not be stored or used within Group A, E, I or U occupancies.
Exception: Cylinders not exceeding 20 cubic feet (0.566 m3) at normal temperature and pressure (NTP) are allowed within gas cabinets or fume hoods.
Toxic and highly toxic compressed gases shall not be stored or used in offices, retail sales or classroom portions of Group B, F, M or S occupancies.
Exception: In classrooms of Group B occupancies, cylinders with a capacity not exceeding 20 cubic feet (0.566 m3) at NTP are allowed in gas cabinets or fume hoods.
Gas cabinets containing highly toxic or toxic compressed gases shall comply with Section 5003.8.6 and the following requirements:
- The average ventilation velocity at the face of gas cabinet access ports or windows shall be not less than 200 feet per minute (1.02 m/s) with not less than 150 feet per minute (0.76 m/s) at any point of the access port or window.
- Gas cabinets shall be connected to an exhaust system.
- Gas cabinets shall not be used as the sole means of exhaust for any room or area.
- The maximum number of cylinders located in a single gas cabinet shall not exceed three, except that cabinets containing cylinders not exceeding 1 pound (0.454 kg) net contents are allowed to contain up to 100 cylinders.
- Gas cabinets required by Section 6004.2 or 6004.3 shall be equipped with an approved automatic sprinkler system in accordance with Section 903.3.1.1. Alternative fire-extinguishing systems shall not be used.
Exhausted enclosures containing highly toxic or toxic compressed gases shall comply with Section 5003.8.5 and the following requirements:
- The average ventilation velocity at the face of the enclosure shall be not less than 200 feet per minute (1.02 m/s) with not less than 150 feet per minute (0.76 m/s).
- Exhausted enclosures shall be connected to an exhaust system.
- Exhausted enclosures shall not be used as the sole means of exhaust for any room or area.
- Exhausted enclosures required by Section 6004.2 or 6004.3 shall be equipped with an approved automatic sprinkler system in accordance with Section 903.3.1.1. Alternative fire-extinguishing systems shall not be used.
One or more gas cabinets or exhausted enclosures shall be provided to handle leaking cylinders, containers or tanks.
Exceptions:
- Where cylinders, containers or tanks are located within gas cabinets or exhausted enclosures.
Where approved containment vessels or containment systems are provided in accordance with all of the following:
- 2.1. Containment vessels or containment systems shall be capable of fully containing or terminating a release.
- 2.2. Trained personnel shall be available at an approved location.
- 2.3. Containment vessels or containment systems shall be capable of being transported to the leaking cylinder, container or tank.
In addition to the requirements of Section 5003.2.2, piping and controls on stationary tanks shall comply with the following requirements:
Pressure relief devices shall be vented to a treatment system designed in accordance with Section 6004.2.2.7.
Exception: Pressure relief devices on outdoor tanks provided exclusively for relieving pressure due to fire exposure are not required to be vented to a treatment system provided that:
- The material in the tank is not flammable.
- The tank is not located in a diked area with other tanks containing combustible materials.
- The tank is located not less than 30 feet (9144 mm) from combustible materials or structures or is shielded by a fire barrier complying with Section 6004.3.2.1.1.
- Filling or dispensing connections shall be provided with a means of local exhaust. Such exhaust shall be designed to capture fumes and vapors. The exhaust shall be directed to a treatment system in accordance with Section 6004.2.2.7.
Stationary tanks shall be provided with a means of excess flow control on all tank inlet or outlet connections.
Exceptions:
- Inlet connections designed to prevent backflow.
- Pressure relief devices.
Gas rooms shall comply with Section 5003.8.4 and both of the following requirements:
- The exhaust ventilation from gas rooms shall be directed to an exhaust system.
- Gas rooms shall be equipped with an approved automatic sprinkler system. Alternative fire-extinguishing systems shall not be used.
The exhaust ventilation from gas cabinets, exhausted enclosures and gas rooms, and local exhaust systems required in Sections 6004.2.2.4 and 6004.2.2.5 shall be directed to a treatment system. The treatment system shall be utilized to handle the accidental release of gas and to process exhaust ventilation. The treatment system shall be designed in accordance with Sections 6004.2.2.7.1 through 6004.2.2.7.5 and Section 510 of the International Mechanical Code.
Exceptions:
Highly toxic and toxic gases—storage. A treatment system is not required for cylinders, containers and tanks in storage where all of the following controls are provided:
- 1.1. Valve outlets are equipped with gas-tight outlet plugs or caps.
- 1.2. Handwheel-operated valves have handles secured to prevent movement.
- 1.3. Approved containment vessels or containment systems are provided in accordance with Section 6004.2.2.3.
- Toxic gases—use. Treatment systems are not required for toxic gases supplied by cylinders or portable tanks not exceeding 1,700 pounds (772 kg) water capacity where a gas detection system complying with Section 6004.2.2.10 and listed or approved automatic-closing fail-safe valves are provided. The gas detection system shall have a sensing interval not exceeding 5 minutes. Automatic-closing fail-safe valves shall be located immediately adjacent to cylinder valves and shall close when gas is detected at the permissible exposure limit (PEL) by a gas sensor monitoring the exhaust system at the point of discharge from the gas cabinet, exhausted enclosure, ventilated enclosure or gas room.
The maximum flow rate of release for portable tanks and cylinders shall be calculated based on the total release from the cylinder or tank within the time specified in Table 6004.2.2.7.5. Where portable tanks or cylinders are equipped with approved excess flow or reduced flow valves, the worst-case release shall be determined by the maximum achievable flow from the valve as determined by the valve manufacturer or compressed gas supplier. Reduced flow and excess flow valves shall be permanently marked by the valve manufacturer to indicate the maximum design flow rate. Such markings shall indicate the flow rate for air under normal temperature and pressure.
| VESSEL TYPE | NONLIQUEFIED (minutes) | LIQUEFIED (minutes) |
| Containers | 5 | 30 |
| Portable tanks | 40 | 240 |
Emergency power shall be provided for the following systems in accordance with Section 604:
- Exhaust ventilation system.
- Treatment system.
- Gas detection system.
- Smoke detection system.
- Temperature control system.
- Fire alarm system.
- Emergency alarm system.
A gas detection system complying with Section 916 shall be provided to detect the presence of gas at or below the PEL or ceiling limit of the gas for which detection is provided. The system shall be capable of monitoring the discharge from the treatment system at or below one-half the IDLH limit and shall initiate a response in accordance with Sections 6004.2.2.10.1 through 6004.2.2.10.3 if the gas detection alarm is activated.
Exception: A gas detection system is not required for toxic gases when the physiological warning threshold level for the gas is at a level below the accepted PEL for the gas.
The gas detection system shall initiate a local alarm and transmit a signal to a constantly attended control station when a short-term hazard condition is detected. The alarm shall be both audible and visible and shall provide warning both inside and outside the area where gas is detected. The audible alarm shall be distinct from all other alarms.
Exception: Signal transmission to a constantly attended control station is not required where not more than one cylinder of highly toxic or toxic gas is stored.
The gas-detection system shall automatically close the shutoff valve at the source on gas supply piping and tubing related to the system being monitored for whichever gas is detected.
Exception: Automatic shutdown is not required for reactors utilized for the production of highly toxic or toxic compressed gases where such reactors are:
- Operated at pressures less than 15 pounds per square inch gauge (psig) (103.4 kPa).
- Constantly attended.
- Provided with emergency shutoff valves that have ready access.
Automatic closure of shutoff valves shall be in accordance with the following:
- Where the gas-detection sampling point initiating the gas detection system alarm is within a gas cabinet or exhausted enclosure, the shutoff valve in the gas cabinet or exhausted enclosure for the specific gas detected shall automatically close.
- Where the gas-detection sampling point initiating the gas detection system alarm is within a gas room and compressed gas containers are not in gas cabinets or exhausted enclosures, the shutoff valves on all gas lines for the specific gas detected shall automatically close.
- Where the gas-detection sampling point initiating the gas detection system alarm is within a piping distribution manifold enclosure, the shutoff valve for the compressed container of specific gas detected supplying the manifold shall automatically close.
Exception: Where the gas-detection sampling point initiating the gas-detection system alarm is at a use location or within a gas valve enclosure of a branch line downstream of a piping distribution manifold, the shutoff valve in the gas valve enclosure for the branch line located in the piping distribution manifold enclosure shall automatically close.
Outdoor storage or use of highly toxic or toxic compressed gases shall be located in accordance with Sections 6004.3.2.1.1 through 6004.3.2.1.3.
Exception: Compressed gases located in gas cabinets complying with Sections 5003.8.6 and 6004.1.2 and located 5 feet (1524 mm) or more from buildings and 25 feet (7620 mm) or more from an exit discharge.
Outdoor storage or use of highly toxic or toxic compressed gases shall not be located within 75 feet (22 860 mm) of a lot line, public street, public alley, public way, exit discharge or building not associated with the manufacture or distribution of such gases, unless all of the following conditions are met:
- Storage is shielded by a 2-hour fire barrier that interrupts the line of sight between the storage and the exposure.
- The 2-hour fire barrier shall be located not less than 5 feet (1524 mm) from any exposure.
- The 2-hour fire barrier shall not have more than two sides at approximately 90-degree (1.57 rad) directions, or three sides with connecting angles of approximately 135 degrees (2.36 rad).
Weather protection in accordance with Section 5004.13 shall be provided for portable tanks and cylinders located outdoors and not within gas cabinets or exhausted enclosures. The storage area shall be equipped with an approved automatic sprinkler system in accordance with Section 903.3.1.1.
Exception: An automatic sprinkler system is not required where:
- All materials under the weather protection structure, including hazardous materials and the containers in which they are stored, are non-combustible.
- The weather protection structure is located not less than 30 feet (9144 mm) from combustible materials or structures or is separated from such materials or structures using a fire barrier complying with Section 6004.3.2.1.1.
Ozone gas generators having a maximum ozone-generating capacity of 0.5 pound (0.23 kg) or more over a 24-hour period shall be in accordance with Sections 6005.2 through 6005.6.
Exceptions:
- Ozone-generating equipment used in Group R-3 occupancies.
- Ozone-generating equipment where used in Group H-5 occupancies where in compliance with Chapters 27 and 50 and the other provisions in this chapter for highly toxic gases.
Ozone generators shall be located in approved cabinets or ozone generator rooms in accordance with Section 6005.3.1 or 6005.3.2.
Exception: An ozone gas generator within an approved pressure vessel where located outside of buildings.
Ozone cabinets shall be constructed of approved materials and compatible with ozone. Cabinets shall display an approved sign stating: OZONE GAS GENERATOR—HIGHLY TOXIC—OXIDIZER.
Cabinets shall be braced for seismic activity in accordance with the International Building Code.
Cabinets shall be mechanically ventilated in accordance with the International Mechanical Code with not less than six air changes per hour.
The average velocity of ventilation at makeup air openings with cabinet doors closed shall be not less than 200 feet per minute (1.02 m/s).
Ozone gas generator rooms shall be mechanically ventilated in accordance with the International Mechanical Code with not less than six air changes per hour. Ozone gas generator rooms shall be equipped with a gas detection system complying with Section 916 that will shut off the generator and sound a local alarm when concentrations above the permissible exposure limit (PEL) occur.
Ozone gas generator rooms shall not be normally occupied, and such rooms shall be kept free of combustible and hazardous material storage. Room access doors shall display an approved sign stating: OZONE GAS GENERATOR—HIGHLY TOXIC—OXIDIZER.
Piping shall be welded stainless steel piping or tubing.
Exceptions:
- Double-walled piping.
- Piping, valves, fittings and related components located in exhausted enclosures.
Ozone gas generators shall be designed to shut down automatically under the following conditions:
- When the dissolved ozone concentration in the water being treated is above saturation when measured at the point where the water is exposed to the atmosphere.
- When the process using generated ozone is shut down.
- Failure of the ventilation system for the cabinet or ozone generator room.
- Failure of the gas detection system in an ozone gas generator room.
