The Definition of Self-Contained Self-Rescuer (SCSR)

Definition of Self-Contained Self-Rescuer (SCSR)

A self-contained self-rescuer (SCSR) is a closed-circuit breathing device that supplies oxygen independent of the surrounding atmosphere so a miner can escape a fire, explosion, smoke or oxygen-deficient air.

Underground mine emergencies can fill entries with smoke, toxic gases and air that has too little oxygen to support life. Carbon monoxide from fires and explosions is a major killer, and carbon monoxide poisoning can overcome a person before they notice symptoms. An SCSR gives the wearer a sealed supply of breathable air for long enough to reach fresh air, a cache of more SCSRs, or a refuge alternative.

Under MSHA rules, SCSRs are required equipment in underground coal mines and are used in some underground metal and nonmetal mines. Every miner, foreman, mechanic and visitor who goes underground in a coal mine must have one available. Mine rescue planning, escapeway design and the mine's emergency action plan are all built around where SCSRs are stored and how long they last.

How a Self-Contained Self-Rescuer Works

Types of SCSR

• Chemical oxygen units: use a chemical such as potassium superoxide that reacts with moisture and carbon dioxide in exhaled breath to release oxygen. The wearer rebreathes the same air in a closed loop.
• Compressed oxygen units: carry a small cylinder of oxygen that feeds a breathing bag, with a chemical scrubber removing carbon dioxide from exhaled air.

SCSR vs Filter Self-Rescuer

• Filter self-rescuer: a filter device that converts carbon monoxide to carbon dioxide. It only works when the air still has enough oxygen to breathe.
• SCSR: supplies its own oxygen and does not rely on the mine air at all. It protects against smoke, toxic gases and an asphyxiant atmosphere where oxygen is low.

Donning and Transferring

• Donning: the miner opens the unit, starts the oxygen supply, inserts the mouthpiece, puts on the nose clip and goggles, and secures the unit. Speed matters, so the steps must be practiced until they are automatic.
• Transferring: when one unit is running low, the miner switches to a fresh SCSR from a cache without breathing the mine air in between.
• Rated duration: each unit is rated for a set time under test conditions. Real duration depends on how hard the wearer is breathing, walking or crawling.

Regulations and Standards

MSHA Underground Coal: 30 CFR Part 75

• 30 CFR 75.1714: each operator must make available to each person underground an approved self-rescue device or devices adequate to protect that person for at least 1 hour.
• 30 CFR 75.1714-3: SCSRs must be inspected and maintained according to the manufacturer's instructions. Units that are damaged or past their service life must be removed from service.
• 30 CFR 75.1714-4: additional SCSRs must be stored along escapeways in caches and at other locations where needed so miners can reach a fresh unit during escape.
• 30 CFR 75.1504: miners must receive quarterly training in donning and transferring SCSRs, plus annual expectations training that is realistic, such as training in smoke or simulated smoke.

These requirements expanded after the Mine Improvement and New Emergency Response Act of 2006 (the MINER Act), which followed several deadly coal mine disasters.

MSHA Metal and Nonmetal: 30 CFR Part 57

In underground metal and nonmetal mines, 30 CFR 57.15030 requires that a self-rescue device approved for protection against carbon monoxide be available to each person underground. Depending on conditions, this may be a filter self-rescuer or an SCSR.

Approval: 42 CFR Part 84

SCSRs are approved by NIOSH and MSHA under 42 CFR Part 84, the federal standard for respirator approval. Only approved units may be used to meet the mining rules. SCSRs are a specialized form of respiratory protection meant for escape, not for work or rescue entry.

Good Practices for Self-Contained Self-Rescuers

• Keep units within reach: each person should carry or have their assigned SCSR close enough to reach and don it quickly in an emergency.
• Practice donning: train until miners can don a unit quickly, by feel, in low visibility. Use training units that mimic the real device.
• Run realistic drills: include smoke or simulated smoke, walking with the unit on, and transferring to a cache unit.
• Inspect every shift: check seals, indicators and cases at the start of each shift and remove any damaged unit from service.
• Track service life: log serial numbers, deployment dates and expiration dates so units are replaced on time.
• Know the caches: make sure miners know where SCSR caches are along both escapeways and how far apart they are.

Example of a Self-Contained Self-Rescuer (SCSR)

An underground coal mine ran its quarterly SCSR training in a classroom. During an unannounced escape drill, a section crew had to don training units and walk the primary escapeway in simulated smoke. Two miners struggled to get their nose clips and goggles on, and one removed his mouthpiece to talk to the crew. In a real fire with carbon monoxide present, that could have been fatal.

The mine changed its training to hands-on donning drills with training units at every quarterly session, plus regular smoke-tent exercises. Crews practiced communicating with hand signals and a knotted lifeline instead of removing mouthpieces. The safety department also added a shift-start SCSR check to the section foreman's examination and audited cache locations against the mine map.

Frequently Asked Questions: Self-Contained Self-Rescuer (SCSR)

How long does an SCSR last?

Under 30 CFR 75.1714, the device or devices available to each person in an underground coal mine must protect them for at least 1 hour. Actual duration depends on the unit and on how hard the wearer is breathing, so caches along escapeways provide more units.

What is the difference between an SCSR and a filter self-rescuer?

A filter self-rescuer only converts carbon monoxide and needs enough oxygen in the air to work. An SCSR supplies its own oxygen, so it protects in smoke and in oxygen-deficient atmospheres.

How often must miners train on SCSRs?

In underground coal mines, 30 CFR 75.1504 requires quarterly training in donning and transferring SCSRs. Miners also receive annual expectations training that is realistic, such as training in smoke or simulated smoke.

Who approves SCSRs?

SCSRs are approved jointly by NIOSH and MSHA under 42 CFR Part 84. Mines must use approved units and maintain them according to the manufacturer's instructions.