WP-1 Wave Pool — Caisson and Pump Vault Isolation
Maintenance inside a wave pool caisson and pump vault. Covers the pneumatic blowers that generate the wave, surge chamber stored pressure, entrapment at the pool interface, and the chemical dosing lines that keep running.
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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.
12 points, in sequence
Pool closure and physical barriers at the water surface above the vault.
Method: Confirm the pool is closed to the public and barriers are in place. Must remain in place.
Caution: The public do not know there is a crew under the pool floor. Closure is part of the isolation, not housekeeping.
Wave blower number one motor disconnect, 200 hp.
Method: Open, lock, prove dead at the starter.
Caution: The wave sequence runs unattended on a timer. A blower that is stopped is not a blower that is isolated.
Wave blower number two motor disconnect, 200 hp.
Method: Open, lock, prove dead at the starter.
Caution: Both blowers must be isolated. The sequencer alternates between them and will select the one that was left available.
Wave sequencer and programmable controller supply.
Method: Open and lock the controller supply.
Caution: Isolating blowers without the sequencer leaves a controller that will energise valves and dampers on schedule.
Surge chamber pressure relief and vent to atmosphere.
Method: Open the vent and lock open. Confirm the chamber gauge reads zero before opening the caisson access hatch.
Caution: The surge chamber holds pressure after the blowers stop. Opening the hatch against residual pressure launches it.
Caisson discharge damper between the surge chamber and the pool.
Method: Drive the damper closed, pin it, and confirm the pin is seated. Must be ENGAGED.
Caution: An unpinned damper drops under its own weight into the caisson the crew is standing in.
Pool circulation pump disconnect feeding the vault suction.
Method: Open and lock.
Caution: Circulation suction at the pool floor is an entrapment hazard for anyone in the water above the vault.
Vault suction isolation valve at the pool interface.
Method: Close and lock the suction valve. Confirm the vault will not flood from the pool side.
Caution: The pool is full and above the vault. This valve is what stands between the crew and the pool volume.
Chlorine and acid dosing lines passing through the vault.
Method: Close and lock both dosing valves, then bleed the injection lines at the sample port.
Caution: Dosing lines run at pressure through the vault. A line broken during work sprays concentrated chemical in a confined space.
Vault sump drain and dewatering pump.
Method: Do NOT isolate. Confirm the dewatering pump is running and the sump is clear before entry.
Caution: A vault below pool level takes water in. The dewatering pump is what keeps it survivable.
Forced ventilation into the caisson and vault.
Method: Do NOT isolate. Confirm continuous ventilation for the duration of the entry.
Caution: Chlorine vapour and CO2 collect in the low point of the vault.
Atmospheric monitoring at the vault floor and on each entrant.
Method: Do NOT isolate. Confirm calibration is current before entry.
Caution: This is a permit-required confined space under 1910.146. Monitoring is the entry control.
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.