WAC 296-155-20301   Definitions.  Confined space means a space that:

     (1) Is large enough and so configured that an employee can bodily enter and perform assigned work; and

     (2) Has limited or restricted means for entry or exit (for example, tanks, vessels, silos, storage bins, hoppers, vaults, and pits are spaces that may have limited means of entry); and

     (3) Is not designed for continuous employee occupancy.

     "Corrosives" means substances which in contact with living tissue cause destruction of the tissue by chemical action.

     "Hazardous atmosphere" means an atmosphere that may expose employees to the risk of death, incapacitation, impairment of ability to self-rescue (that is, escape unaided from a permit space), injury, or acute illness from one or more of the following causes:

     (1) Flammable gas, vapor, or mist in excess of ten percent of its lower flammable limit (LFL);

     (2) Airborne combustible dust at a concentration that meets or exceeds its LFL;

Note:

This concentration may be approximated as a condition in which the dust obscures vision at a distance of five feet (1.52m) or less.

     (3) Atmospheric oxygen concentration below 19.5 percent or above 23.5 percent;

     (4) Atmospheric concentration of any substance for which a dose or a permissible exposure limit is published in chapter 296-62 WAC, general occupational health standards, or chapter 296-841 WAC, Airborne contaminants, and which could result in employee exposure in excess of its dose or permissible exposure limit;

Note:

An atmospheric concentration of any substance that is not capable of causing death, incapacitation, impairment of ability to self-rescue, injury, or acute illness due to its health effects is not covered by this provision.

     (5) Any other atmospheric condition that is immediately dangerous to life or health.

Note:

For air contaminants for which WISHA has not determined a dose or permissible exposure limit, other sources of information, such as material safety data sheets that comply with the Chemical Hazard Communication Standard, WAC 296-800-170, published information, and internal documents can provide guidance in establishing acceptable atmospheric conditions.

     "Irritants" means substances which on immediate, prolonged, or repeated contact with normal living tissue will induce a local inflammatory reaction.

     "Oxygen deficient atmospheres" means atmospheres at sea level having less than 19.5% oxygen by volume or having a partial pressure of 148 millimeters of mercury or less. This may deviate when working at higher altitudes and should be determined for an individual location. Factors such as acclimatization, physical condition of persons involved, etc., must be considered for such circumstances and conditions. (See chapter 296-62 WAC, Part M, permit-required confined spaces.)

     "Toxicants" means substances which have the inherent capacity to produce personal injury or illness to persons by absorption through any body surface.



[Statutory Authority: RCW 49.17.010, 49.17.040, 49.17.050, 49.17.060. 07-05-062, § 296-155-20301, filed 2/20/07, effective 4/1/07; 05-03-093, § 296-155-20301, filed 1/18/05, effective 3/1/05. Statutory Authority: RCW 49.17.010,[49.17].040 , and [49.17].050. 01-11-038, § 296-155-20301, filed 5/9/01, effective 9/1/01. Statutory Authority: RCW 49.17.040, [49.17].050 and [49.17].060. 95-17-036, § 296-155-20301, filed 8/9/95, effective 9/25/95. Statutory Authority: Chapter 49.17 RCW. 95-04-007, § 296-155-20301, filed 1/18/95, effective 3/1/95; 91-24-017 (Order 91-07), § 296-155-20301, filed 11/22/91, effective 12/24/91. Statutory Authority: RCW 49.17.040 and 49.17.050. 86-03-074 (Order 86-14), § 296-155-20301, filed 1/21/86.]