Lesson 3Confined Spaces
Confined spaces include pipe chases (areas within and under buildings where steam and utility pipes are run) and valve pits (areas below grade that contain utility shut-off valves). Working in confined areas presents numerous challenges. Movement and communication are difficult and, if a problem arises, immediate exit from the area may be impossible.
The air in some confined spaces may be contaminated or low in oxygen, posing significant health risks for workers. Efficient rescue of an injured worker may be difficult or impossible. Poor lighting may result in increased injuries. Because exposures may be greatly magnified in a confined space, workers must use a higher level of PPE than they would when working in a more accessible area.
Worker safety must be carefully considered when deciding whether to use disinfectants or biocides because confined spaces may increase the potential for exposure. In general, work in confined spaces should be conducted only by trained professionals who have the equipment required by OSHA to deal with the inherent dangers in this type of environment.
Before remediating mold in a confined space, the area should be evaluated for atmosphere and toxic substances. If there is any chance of low oxygen, the area should be tested using the appropriate equipment. The testing equipment should be kept on site and used periodically to ensure an adequate oxygen supply. If the area is sealed off from the rest of the building to prevent the spread of mold spores, oxygen testing should be conducted again after the area has been sealed. A frequent contaminant in crawlspaces and pipe chases of older buildings is asbestos; other chemicals such as natural gas and solvents can also be found in some of these spaces. These materials must be identified and dealt with properly to prevent worker exposure.
Once the hazards have been identified, procedures for working in the confined space should be included in the remediation plan. Special consideration should be given to who will be allowed into the area, how communications will be maintained, what materials can be taken into or used in the space, and what safety equipment is necessary. Only individuals trained in the hazards associated with that space should be allowed to enter. An attendant should be posted outside of the confined space area to summon help if necessary. The area should be well lit so that work can be conducted efficiently and injuries avoided.
In conducting the mold remediation, every effort should be made to keep dust and mold out of the air. This can be done by using moist techniques, such as a damp cloth or pad, for mold removal and by bagging the material in the confined space for later removal. Mold levels are likely to be high in a confined space, so PPE should be selected accordingly. Most cases will require full PPE, including skin and eye protection, and full respiratory protection using a full-face respirator or a powered air purifying respirator (PAPR) with a HEPA filter. The presence of asbestos may require other PPE for workers as well as monitoring and medical evaluation.