MUD-T2 Confined Space Entry - Tank Clean and Inspect
Permit-required confined space entry into mud tank no.2 for cleaning and internal inspection. 29 CFR 1910.146.
It refers to equipment that does not exist and illustrates the elements 29 CFR 1910.147(c)(4)(ii) requires a procedure to contain. It is not a document to adopt. Under (c)(4)(i) the employer must develop and document energy control procedures specific to their own machines, and under (c)(6) must inspect them at least annually.
Other standards also apply to this work
- 29 CFR 1910.146 — permit-required confined spaces. Entry requires its own permit, attendant and rescue provisions beyond the energy isolation shown here.
12 points, in sequence
Tank no.2 agitator motor disconnect at the MCC. Blades start without warning if energised.
Mud gun supply valve to tank no.2. High-pressure jet - can injure or knock an entrant off balance.
Suction line valve to mud pumps 1 and 2. ENGULFMENT - tank can drain or backfill through this line.
Transfer line valve from the reserve pit. Second fill path - often missed.
Fill line spectacle blind turned to the BLANK position. Positive isolation - a closed valve is not enough for entry.
Retrieval tripod, winch and full-body harness rigged at the top hatch. Vertical entry - retrieval line stays attached.
Forced-air ventilation blower. Must RUN CONTINUOUSLY - ventilation controls the atmosphere, it does not eliminate the hazard.
Continuous four-gas monitor in the space. Must REMAIN LIVE - entrants evacuate on alarm.
Class 1 Division 1 rated task lighting in the tank. Must REMAIN LIVE - no other light source is permitted.
Oxygen concentration at three levels in the tank. Acceptable 19.5 to 23.5 percent.
Lower explosive limit. Acceptable below 10 percent LEL.
Hydrogen sulphide. Acceptable below 10 ppm. Mud systems on sour wells can hold H2S in the sludge.
What your site must supply
This example is structurally complete and factually generic. The things below are the things only you can know — and they are exactly what makes a procedure yours.
- Your own asset and isolation-point tag numbers. The tags shown are illustrative and refer to equipment that does not exist.
- The actual location of every disconnect, valve and vent on your equipment.
- Measured stored-energy magnitudes and the dwell time required to dissipate them.
- Your verification method for each point, and who is authorised to perform it.
- Any additional energy sources present on your equipment and absent here.
Author this properly, once
Setyr holds procedures like this as living documents — bound to real isolation points, with lock registries, group lockout, person-in-charge custody and periodic review built in.