All permit confined space will require a second person as an attendant. Any other space which requires the Emergency Retrieval System, also requires an attendant. If work or activity in the tunnel changes the air quality in the tunnel, additional precautions will be necessary. For example, if chilled water lines are being vented, continuous air monitoring must be conducted throughout the venting operation. The venting must exhaust outside the tunnel.
Air monitoring is required if the draft fans are off.
Each work space must be evaluated separately. The need for shoes, eye wear, hard hat, protective clothing and gloves should be evaluated separately from the confined space hazards. Respirators should only be worn in conjunction with an approved respiratory protection program, which includes medical surveillance, fit testing, written plans and more. A portable ladder may be used to gain entry into a confined space. The tripod and winch assembly may be used to lower a person into a confined space.