Setyr worked example — MUD-T2 Confined Space Entry - Tank Clean and Inspect Not approved for use. Version 1 · 2026-09-04
Worked example only — your site must author, review and approve its own
procedure under 29 CFR 1910.147(c)(4). setyr.com/procedures
MUD-T2 Confined Space Entry - Tank Clean and Inspect
Water & wastewater
Permit-required confined space entry into mud tank no.2 for cleaning and internal inspection. 29 CFR 1910.146.
This is a worked example, not a procedure you can adopt. It describes equipment that does not exist, with illustrative tag numbers.
29 CFR 1910.147(c)(4) requires the employer to develop, document and
utilise energy control procedures specific to their own machines, and (c)(6)
requires the employer to inspect those procedures periodically. Neither duty
can be delegated to a vendor or discharged by this document.
Other standards 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.
Isolation points
| # | Tag (illustrative) | Type | Disposition | What it does and why | Dwell |
|---|---|---|---|---|---|
| 10 | MUD-T2-AGITATOR | Disconnect | Isolate & lock | Tank no.2 agitator motor disconnect at the MCC. Blades start without warning if energised. | — |
| 20 | MUD-T2-MUDGUN | Valve | Isolate & lock | Mud gun supply valve to tank no.2. High-pressure jet - can injure or knock an entrant off balance. | — |
| 30 | MUD-T2-SUCTION | Valve | Isolate & lock | Suction line valve to mud pumps 1 and 2. ENGULFMENT - tank can drain or backfill through this line. | — |
| 40 | MUD-T2-TRANSFER | Valve | Isolate & lock | Transfer line valve from the reserve pit. Second fill path - often missed. | — |
| 50 | MUD-T2-FILL-BLIND | Blind | Apply & verify | Fill line spectacle blind turned to the BLANK position. Positive isolation - a closed valve is not enough for entry. | — |
| 60 | MUD-T2-TRIPOD | Block | Apply & verify | Retrieval tripod, winch and full-body harness rigged at the top hatch. Vertical entry - retrieval line stays attached. | — |
| 70 | MUD-T2-VENT | Disconnect | KEEP ENERGISED | Forced-air ventilation blower. Must RUN CONTINUOUSLY - ventilation controls the atmosphere, it does not eliminate the hazard. | — |
| 80 | MUD-T2-GASMON | Disconnect | KEEP ENERGISED | Continuous four-gas monitor in the space. Must REMAIN LIVE - entrants evacuate on alarm. | — |
| 90 | MUD-T2-LIGHTING | Disconnect | KEEP ENERGISED | Class 1 Division 1 rated task lighting in the tank. Must REMAIN LIVE - no other light source is permitted. | — |
| 100 | MUD-T2-ATM-O2 | Vent | Apply & verify | Oxygen concentration at three levels in the tank. Acceptable 19.5 to 23.5 percent. | — |
| 110 | MUD-T2-ATM-LEL | Vent | Apply & verify | Lower explosive limit. Acceptable below 10 percent LEL. | — |
| 120 | MUD-T2-ATM-H2S | Vent | Apply & verify | Hydrogen sulphide. Acceptable below 10 ppm. Mud systems on sour wells can hold H2S in the sludge. | — |
What your site must supply
- 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.
Authorship and validation
This example was authored by Setyr for domain validation. It is not derived from any customer's controlled documents. It illustrates the elements 29 CFR 1910.147(c)(4)(ii) requires a procedure to contain — it does not certify compliance, which is a property of an employer's programme rather than of any document.