Setyr worked example — LYO-3 Lyophiliser — Chamber Entry and Shelf Stack Isolation Not approved for use. Version 1 · 2026-09-08
Worked example only — your site must author, review and approve its own
procedure under 29 CFR 1910.147(c)(4). setyr.com/procedures
LYO-3 Lyophiliser — Chamber Entry and Shelf Stack Isolation
Pharmaceutical
Shelf stack and condenser service inside a production freeze dryer. Covers hydraulic shelf collapse, clean steam sterilisation heat, silicone thermal fluid at temperature extremes, refrigerant, and vacuum that must be broken before the door.
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 | LYO-3-VAC-BRK | Vent | Isolate & lock | Chamber vacuum break to sterile filtered air. Caution: The door is held by several tonnes of force under vacuum. Forcing it, or releasing it suddenly, is the hazard. Break vacuum through the sterile filter and confirm the chamber is at atmospheric on two independent gauges before touching the door. | 300s |
| 20 | LYO-3-SHELF-HYD | Valve | Isolate & lock | Shelf stack hydraulic cylinder supply, which raises and holds the shelves for stoppering. Caution: A hydraulically held shelf stack collapses onto anyone inside the chamber if pressure is lost. Lower it before isolating, never after. Lower the stack fully onto its mechanical stops, THEN close and lock the hydraulic supply and bleed the accumulator. | 240s |
| 30 | LYO-3-SHELF-BLK | Block | Apply & verify | Mechanical shelf stack supports, inserted before entry. Caution: The supports are the restraint once hydraulics are bled. Hydraulic isolation alone is not enough for chamber entry. Insert the shelf supports at both ends and confirm seated. Must be ENGAGED. | — |
| 40 | LYO-3-MAIN | Disconnect | Isolate & lock | Lyophiliser main disconnect at the plant room panel. Caution: The shelf stack is hydraulically held. Removing electrical supply does not support the shelves. Open, lock, prove dead. | — |
| 50 | LYO-3-STEAM | Valve | Isolate & lock | Clean steam supply for chamber and condenser sterilisation. Caution: A chamber that has just completed sterilisation is at 121 degrees C and stays hot long after the cycle ends. Close and lock the clean steam valve, then allow the chamber to cool and confirm surface temperature before entry. | 900s |
| 60 | LYO-3-SILOIL | Valve | Isolate & lock | Silicone thermal fluid circulation to the shelves, operating between minus 50 and plus 121 degrees C. Caution: The same fluid delivers a cryogenic burn at one end of the cycle and a thermal burn at the other. Isolated does not mean safe to touch. Close and lock supply and return, then allow the shelf circuit to equalise to ambient and confirm at the shelf thermocouple. | 600s |
| 70 | LYO-3-REFRIG | Disconnect | Isolate & lock | Refrigeration compressor supply to the condenser coils. Caution: The condenser holds refrigerant under pressure and its coils sit at minus 60 degrees C for hours after shutdown. Open and lock the compressor disconnect. | — |
| 80 | LYO-3-N2 | Valve | Isolate & lock | Nitrogen backfill supply used for stoppering. Caution: An open nitrogen backfill into an occupied chamber is fatal within minutes and gives no warning. Close and lock the nitrogen supply, then bleed the backfill line. | 120s |
| 90 | LYO-3-CIP | Valve | Isolate & lock | Clean-in-place and WFI rinse supply to the chamber spray balls. Caution: A CIP cycle starting with an entrant inside floods a sealed chamber with hot water. Close and lock the CIP supply valve. | — |
| 100 | LYO-3-ICE | Drain | Isolate & lock | Condenser defrost and ice melt drain. Caution: Ice on the condenser sublimes into the chamber and displaces the atmosphere the entrant is breathing. Open the melt drain and confirm the condenser is clear of ice before entry. | — |
| 110 | LYO-3-DOOR | Block | Apply & verify | Chamber door hydraulic clamp and its mechanical hold-open restraint. Caution: A door that closes on a hydraulic clamp with someone inside seals a pressure vessel around them. Set the door hold-open restraint and confirm engaged before entry. Must remain ENGAGED. | — |
| 120 | LYO-3-O2 | Breaker | KEEP ENERGISED | Oxygen deficiency monitoring inside the chamber and at the door. Caution: Nitrogen backfill and subliming ice both displace oxygen. This is a permit-required confined space under 1910.146. Do NOT isolate. Confirm monitoring is in service and alarming audibly at the door. | — |
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.