Confined spaces can present various hazards, and OSHA has specific regulations to protect workers in these environments. Here's a breakdown of key safety measures:

Definition: A confined space is a space that is relatively small or restricted, such as a tank, boiler, pressure vessel, or small compartment of a ship [1].

Permit-Required Confined Spaces:

• All spaces should be considered permit-required confined spaces until pre-entry procedures prove otherwise [2].
• A Confined Space Entry Permit must be completed before anyone enters a permit-required confined space [2]. This permit verifies the completion of safety measures [2].
• A written copy of operating and rescue procedures must be at the work site for the duration of the job 1, 5.
• If circumstances change or work is interrupted, a new Confined Space Entry Permit must be completed 1, 5.

Atmospheric Hazards and Ventilation:

• The confined space atmosphere must be tested for dangerous air contamination and/or oxygen deficiency before entry [2].
• Minimum parameters to monitor include oxygen deficiency, LFL (Lower Flammable Limit), and hydrogen sulfide concentration 1, 5.
• A written record of pre-entry test results must be made and kept at the work site 1, 5.
• Mechanical ventilation systems should be set at 100% outside air, where applicable [2].
• If testing reveals dangerous conditions that ventilation cannot reduce to safe levels, or if unsafe conditions are expected to develop, specific entry procedures must be followed [2].
• Continuous gas monitoring should be performed during all confined space operations [3].
• Oxygen shall not be used for ventilation purposes 3, 7.

Entry Procedures and PPE:

• All personnel entering must be trained [2].
• If dangerous conditions exist even after ventilation, a self-contained breathing apparatus (SCBA) must be worn [2].
• A standby worker must be present outside the space, ready to provide assistance 1, 4.
• Continuous communication must be maintained between the worker inside and standby personnel [3].
• Safety belts or harnesses with attached lifelines should be used by all workers entering the space, secured outside the entry opening 4, 6.

Welding in Confined Spaces:

• Ventilation is a prerequisite when welding in confined spaces [1].
• Gas cylinders and welding machines must be left outside the confined space [1].
• When welding is suspended for a substantial period, electrodes must be removed from holders, and the machine disconnected from the power source [4].
• Torch valves should be closed, and the gas supply shut off outside the confined area when the torch is not in use [4].
• After welding, the welder should mark the hot metal or provide a warning to other workers [4].

Rescue Procedures:

• A pre-planned rescue procedure is essential 3, 6.
• The standby worker should attempt to remove a disabled worker via their lifeline before entering the space [3].
• Call the fire department for rescue services [3].

Additional Considerations:

• Ensure proper ventilation during welding, cutting, and heating in confined spaces [5].
• When sufficient ventilation cannot be achieved without blocking access, air-line respirators must be used, and an attendant must maintain communication with those inside [5].
• Be aware of potential engulfment hazards and ensure pumps and lines are disconnected, blinded, and locked out [6].
• Survey the surrounding area to avoid hazards like drifting vapors 1, 5.
• Use Class 1, Division 1 rated lighting and electrical equipment when flammable substances are present [3].
• All air replacing withdrawn air must be clean and respirable 3, 7.

Following these guidelines and OSHA standards is crucial for ensuring worker safety in confined spaces.