Everyday Hazmat User’s Training Guide, Page 25

Everyday Hazmat User's Training Guide

Section III Hazardous Materials Management (continued)

Compressed Gases

Definitions
General Requirements
Compressed Gas Storage
Corrosive Gases
Flammable Gases
Oxidizer Gases
Inert Gases
Liquefied Petroleum Gas Storage
Transportation
Examples of Compressed Gases Used in the USDA Forest Service

Compressed gases are any gases or mixture of gases exerting a gauge pressure of 26 pounds per square inch at 68 °F. Federal regulations specify how these gases must be stored and managed. You should also check with your local fire marshal to see if your area has more restrictive requirements.

Definitions

Compressed Gases—The Dangers

Compressed gases are dangerous because they are under pressure and because they may be oxidizers and they may be corrosive, flammable, toxic, or highly toxic. Be sure you know the type of compressed gas you are dealing with so you know the proper management requirements.

See Hazardous Materials Storage Cabinets.
See Keeping Incompatible Hazardous Materials Separated.
See The Transition to Hazardous Waste.
See Hazardous Product Containers.

Gas values in this guide are given in standard cubic feet. The capacities of some types of gas cylinders in standard cubic feet are given in Table A–2–1 on page 55–11 of NFPA 55.

General Requirements

Many types of compressed gas cylinders may be used in USDA Forest Service operations. This page and the next page outline some restrictions that would apply to all types of gas cylinders. Later pages provide additional restrictions for specific types of compressed gases.

Managing Compressed Gas Cylinders

Only trained personnel should handle compressed gases.
Do not allow cylinder valves to become contaminated.
Do not place cylinders so they are part of an electrical circuit.
Do not expose cylinders to temperature extremes; do not use cylinders that have been exposed to fire.
Notify the supplier if a cylinder is leaking, corroded, or has been exposed to fire.
Cap the valve when the cylinder is not in use.
Move cylinders with a handtruck—not by dragging or carrying.
Do not weld sling attachments to cylinders.
Use backflow preventers as part of compressed gas systems.
Only use tools provided by the supplier to open or close valves.
Use pressure regulators; keep valves closed when cylinders are not being used.
Do not refill cylinders or store them in boneyards; return them to the supplier.
Mark empty cylinders as EMPTY and close the valves; return cylinders to the vendor or dispose of them properly.
Check cylinders for corrosion, leaks, or damage; remove defective cylinders from service.
Partially full cylinders or cylinders with residual gas must be treated as full cylinders.
Secure cylinder storage areas against unauthorized entry.
Secure cylinders to a fixed object, mobile devices designed for moving compressed gas cylinders, or within a rack, framework, cabinet, or similar assembly.
Do not position cylinders where they could drop more than half of their height.
Do not expose cylinders to falling objects.
Separate gases by compatibility; when gases present multiple hazards, use the most stringent restrictions.
Separate cylinders of incompatible gases by 20 feet or by 5-foot-tall barrier with a ½-hour fire rating (see page 101 for an explanation of incompatible gases).

Compressed Gas Storage

Storage restrictions differ depending on whether compressed gases are stored indoors or outdoors. These restrictions are in addition to the general requirements on the preceding page.

Indoor Restrictions

Floors of storage areas must be noncombustible or constructed so their combustibility is limited (see NFPA 55).
Shelves used for storing cylinders must be noncombustible.
Rooms and cabinets where compressed gases are stored must be labeled COMPRESSED GAS.
Indoor heating must not spot-heat cylinders to more than 125 °F.

Outdoor Restrictions

Outdoor storage areas may be covered with noncombustible materials, so long as the materials obscure no more than 25 percent of the perimeter.
Outdoor storage areas must be kept clear of dry vegetation and combustible materials for at least 15 feet.
Outdoor control areas must be at least 20 feet from property lines that can be built on, and any street, alley, or public way.
For properties larger than 10,000 square feet, up to two control areas are allowed if they are separated by 50 feet.
For properties larger than 35,000 square feet, additional control areas are allowed if they are separated by at least 300 feet.
Provide physical barriers to prevent cylinders from being damaged by vehicles.
Do not store cylinders on the ground or in an area where water can accumulate.

Be sure to check for specific compressed gas restrictions.

Corrosive Gases

Special restrictions apply to corrosive gases, especially on the amounts of corrosive gases that may be stored. These restrictions are in addition to those on the previous two pages.

Inside Storage

No more than 810 cubic feet of corrosive gas may be stored in each control area. The amount of corrosive gas allowed in a control area may be increased by 100 percent if the cylinders are stored in an approved gas cabinet or in an enclosure with exhaust ventilation.

Outside Storage

No more than 810 cubic feet of corrosive gas may be stored in each control area.

Permit/Exempt Amounts

Storing more than 200 cubic feet of corrosive compressed gas onsite requires a permit from your local fire marshal.

Flammable Gases

Special restrictions apply to flammable gases. These restrictions are in addition to those of the general requirements and indoor and outdoor restrictions explained earlier.

General Storage of Flammable Compressed Gases

Have a fire extinguisher (carbon dioxide or dry chemical) available.
Use nonsparking tools.
Segregate cylinders of flammable gases from oxidizing, pyrophoric (capable of spontaneous ignition), and toxic gases (20 feet minimum).
Do not allow smoking or open flames within 20 feet of the storage area.
Keep flammable compressed gases at least 20 feet away from flammable liquids and solids.
Store cylinders in the upright position (no more than 45 degrees from vertical) unless the cylinder is designed to operate in the horizontal position or has a water volume of less than 1.3 gallons.

The preferred storage locations for flammable compressed gas cylinders (listed in the order of priority) are outdoors, in a separate building, or in a separate room.

Indoor Storage (Not Recommended)

Cylinders of flammable compressed gas can be stored inside a building, but outside storage is recommended. If you wish to store larger quantities of flammable gas indoors, contact your hazmat coordinator.

The only exception is for cylinders that do not hold more than 250 standard cubic feet of gas used for maintenance or to operate equipment. Flammable gas must not be used or stored inside a building unless it is a specially designed hazmat building.

Permit/Exempt Amounts

Storing more than 200 cubic feet of flammable compressed gas onsite requires a permit from your local fire marshal.

Outdoor Storage (Recommended)

Storing flammable compressed gas cylinders outdoors is preferred. If you wish to store large quantities of flammable gas outdoors, contact your hazmat coordinator.

A maximum of 750 cubic feet of gas may be stored in each control area.

A maximum of 15 gallons of liquefied gas may be stored in each control area.

Permit/Exempt Amounts

Storing more than 200 cubic feet of flammable compressed gas onsite requires a permit from your local fire marshal.

Oxidizer Gases

Special restrictions apply to oxidizer gases. These restrictions are in addition to those of the general requirements and indoor and outdoor restrictions explained earlier. Outdoor storage is recommended for oxidizer gases.

General Requirements—Oxidizer Gases

Ensure that equipment and valves used with oxygen and nitrous gases do not become contaminated with oil, grease, or other hydrocarbons.
Store cylinders of oxidizer gases at least 20 feet away from flammable gases, combustibles, oils, and greases.
Limit sources of ignition.

Indoor Storage of Oxidizer Gases (Not Recommended)

The only exception is for cylinders that do not hold more than 250 standard cubic feet of oxidizer gases used for maintenance or to operate equipment. Oxidizer gas must not be used or stored inside a building unless the building is specially designed for hazardous materials.

Outdoor Storage of Oxidizer Gases (Recommended)

No more than 1,500 cubic feet of oxidizer gas can be stored in each control area.

No more than 15 gallons of liquefied oxidizer gas may be stored in each control area.

Permit/Exempt Amounts

A permit from a fire marshal is required to store more than 504 cubic feet of oxidizer compressed gas onsite.

Inert Gas

There is no limit on the amount of compressed inert and asphyxiant gases that may be stored in one storage area.

Permit/Exempt Amounts

A permit is required if you are storing more than 6,000 standard cubic feet of inert compressed gas.

Liquefied Petroleum Gas Storage

This guideline applies to storing and transporting portable cylinders of liquefied petroleum gas (LPG). It does not cover dispensing or system installation. If you have liquefied petroleum gas at your USDA Forest Service unit, a service provider can service the units or you can replace depleted cylinders with full ones. Transporting and servicing LPG compressed gas cylinders is included in the regulations. These restrictions are in addition to those of the general requirements and indoor and outdoor restrictions explained earlier. See your hazmat coordinator for dispensing requirements.

LPG Storage Restrictions (General Requirements)

Only a trained service supplier should dispense LPG.
NO SMOKING signs should be posted and enforced; do not allow open flames, smoking, welding, or other sources of ignition within 20 feet of LPG.

Image of a rectangle shaped sign that reads, DANGER: NO SMOKING.

NO LPG should be vented to the atmosphere.

Image of a rectangle shaped sign that reads, DANGER: LP GAS.

Storage areas must have COMPRESSED GAS and NO SMOKING signs.
If LPG is stored near vehicles, pipes or other suitable barriers should protect the cylinders from being damaged by vehicles.
Cap all valves when storing LPG.
Store LPG cylinders in an upright position (or at least no more than 45 degrees from vertical); the relief valve must be in contact with vapor in the cylinder. This requirement does not apply to cylinders with water volume less than 1.3 gallons (such as fuel canisters for lanterns or camp stoves) or cylinders designed to be used in the horizontal position.
Store LPG cylinders at least 20 feet from flammable and combustible liquids and solids.
Treat empty LPG cylinders as if they were full.
A permit may be required to store, use, handle, or dispense LPG. Check with your local fire marshal.

LPG Indoor Storage (NOT Recommended)

The storage of containers (cylinders and tanks) of LPG is regulated to minimize hazards and protect the safety of personnel. Some specific requirements apply; check with your local fire marshal for possible additional requirements. Indoor storage of LPG is NOT recommended. For additional information on indoor storage of LPG, contact your hazmat coordinator.

Minimize the cylinders’ exposure to excessive temperatures, physical damage, or tampering.
Do not store cylinders near exits, stairways, or areas used to leave a building.
Do not store cylinders on roofs.
Do not store LPG cylinders in basements or low areas where gases could accumulate.

Storage Limits in Areas Accessible to the Public

Cylinders stored in locations accessible to the public may have a maximum water capacity of 2.5 pounds (about 1 pound of LPG). The amount of LPG in all of the containers must not exceed 200 pounds.

Storage Limits in Residences

LPG storage in residences is limited to two DOT-approved cylinders with a maximum water capacity of 2.7 pounds each (about 1 pound of LPG each); for smaller cylinders, their total water capacity must not exceed 5.4 pounds.

Storage Limits in Areas

That Are Not Accessible to the Public Cylinders stored in locations that are not accessible to the public are limited to a maximum of 735 pounds water capacity (three 25-gallon or fifteen 5-gallon cylinders of LPG) per area. Storage areas must be separated by 300 feet if they are on the same floor. Indoors Liquefied Petroleum Gas Storage (NOT Recommended)

LPG Outdoor Storage (Recommended)

There are some restrictions on outdoor storage of LPG. Check with your fire marshal to see how these regulations are applied in your area. Outdoor storage of LPG is recommended. For outdoor storage of large quantities of LPG, contact your hazmat coordinator.

Click on image for larger descriptive view

Minimize the cylinders’ exposure to excessive temperatures, physical damage, or tampering.
Cylinders stored in locations accessible to the public must be enclosed in a lockable, well-ventilated enclosure or rack.
The storage area must be at least 20 feet from any doorway or opening in a building.
An outdoor storage area may be covered if the cover and supports are of noncombustible construction and no more than 25 percent of the area’s perimeter is obstructed.
Combustible materials (such as weeds) must be removed within 10 feet of LPG cylinders.