Setyr worked example — LS-12 Lift Station — Submersible Pump Pull Isolation Not approved for use. Version 1 · 2026-09-25
Worked example only — your site must author, review and approve its own
procedure under 29 CFR 1910.147(c)(4). setyr.com/procedures
LS-12 Lift Station — Submersible Pump Pull Isolation
Wastewater collection
Removing a submersible sewage pump from a wet well. Covers duty and standby pump isolation, discharge check valve backflow, and the confined-space atmosphere over a live wet well that keeps filling during the work.
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.
Isolation points
| # | Tag (illustrative) | Type | Disposition | What it does and why | Dwell |
|---|---|---|---|---|---|
| 10 | LS-12-BYPASS | Valve | KEEP ENERGISED | Bypass pumping connection to keep incoming flow off the wet well during the pull. Caution: Sewage keeps arriving whether or not the station is working. Without bypass the well rises under the crew. Do NOT isolate. Confirm the bypass pump is running and taking the incoming flow before entry. | — |
| 20 | LS-12-P1-ISO | Disconnect | Isolate & lock | Duty pump motor disconnect at the control panel, 40 hp submersible. Caution: The pump is 8 m down in effluent and cannot be observed. Absence of noise is not proof it is isolated. Open, lock, prove dead at the panel load side. | — |
| 30 | LS-12-P2-ISO | Disconnect | Isolate & lock | Standby pump motor disconnect. Caution: Level controls start the standby automatically when the well rises and the duty pump is unavailable. That is exactly the condition this job creates. Open and lock. The standby must be isolated even though it is not the pump being pulled. | — |
| 40 | LS-12-GEN | Switch | Isolate & lock | Standby generator and its automatic transfer switch. Caution: An ATS in AUTO restores the station from the generator during a supply interruption, re-energising pumps that were isolated at the utility side only. Place the generator in OFF and lock the transfer switch out of AUTO. | — |
| 50 | LS-12-CTRL | Breaker | Isolate & lock | Level control panel supply feeding float switches, the level transducer and the autodialler. Caution: Isolating controls stops automatic starts but also stops high-level alarming. Do not leave the well unmonitored. Open and lock the control supply after confirming the alternative level alarm is in place. | — |
| 60 | LS-12-GRINDER | Disconnect | Isolate & lock | Inlet channel grinder upstream of the wet well. Caution: The grinder sits in the same channel the crew reaches into to clear the guide rail. Open and lock the grinder disconnect. | — |
| 70 | LS-12-P1-DISCH | Valve | Isolate & lock | Duty pump discharge isolation valve on the rising main. Caution: The rising main holds a static head. Lifting a pump without closing discharge drains the main back into the well and over the crew. Close and lock the discharge valve before breaking the pump from its guide rail. | — |
| 80 | LS-12-P1-CHK | Valve | Not an isolation device | Duty pump discharge check valve in the valve chamber. Caution: A check valve is a backflow device. Crews treat it as isolation because it usually holds. It is not, and it is not lockable. Confirm the check valve is seated. It is not a lockable isolation device and does not substitute for the discharge valve. | — |
| 90 | LS-12-VENT | Breaker | KEEP ENERGISED | Forced-air ventilation blower into the wet well. Caution: H2S and methane accumulate in the well headspace. Ventilation is a control, not a convenience. Do NOT isolate. Confirm continuous ventilation for the duration of the entry. | — |
| 100 | LS-12-GAS-MON | Breaker | KEEP ENERGISED | Continuous atmospheric monitoring at the well head and on each entrant. Caution: A wet well is IDLH-capable. Monitoring is the entry control under 1910.146. Do NOT isolate. Confirm calibration is current and alarms are audible at the surface. | — |
| 110 | LS-12-HOIST | Disconnect | KEEP ENERGISED | Davit and hoist over the wet well used to lift the pump on its guide rail. Caution: Isolating the station panel takes the hoist supply with it on this design. Do NOT isolate. Confirm the davit is rated, seated in its socket and the hoist is functional before the lift. | — |
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.