What this is
What is a refrigeration plant log?
What is a refrigeration plant log?
It is the shift record kept by the plant attendant capturing suction and discharge pressures, oil levels, run hours and system health across every compressor on the plant, alongside the ammonia detection and machinery room safety checks that go with an ammonia system. It is a singleton register, set up once per plant and run every shift.
Why does the log repeat per compressor rather than record the plant as a whole?
Because a shared condenser can mask one compressor's decline behind another's healthy running. Recording pressure, temperature and oil level per compressor reference lets a reviewer see one unit trending down while the rest of the plant looks fine.
What does 'within operating envelope' mean for a compressor?
It means suction pressure, discharge pressure and discharge temperature together sit inside the manufacturer's range for that refrigerant and load, not that any single reading looks acceptable alone. A compressor can show normal suction pressure and still be outside its envelope on discharge temperature.
Scope
When is a refrigeration plant log required?
This is a shift-by-shift operating log for the refrigeration plant, not a substitute for the ammonia system safety review or the environmental leak register. Using it to cover ground that belongs to a neighbouring template breaks the trend it exists to build.
Use this template when
- A plant attendant is on shift and needs to record compressor, system and safety parameters at the round
- A new refrigeration plant or compressor is being brought into the register for the first time
- You are running the Pressure Systems and Refrigeration programme and this log is one of its evidence points
- A linked record depends on this one existing, such as the refrigerant leak register or condition monitoring
- A compressor trend needs to be traced back to the shift conditions that preceded a trip or alarm
Do not use it for
- Boiler Operation Record, which records boiler operating parameters and water treatment through a shift, not refrigeration plant.
- Environmental Aspects Register, which is the standing register for refrigerant leaks rather than the shift-level operating trend.
- Refrigeration Unit Service Record, which documents planned and reactive maintenance work rather than routine shift observation.
- Ammonia System Safety Review, which is the periodic safety assessment of the ammonia system as a whole, not the per-shift attendant log.
- Anything outside KnowMaintain, which belongs to the workspace that owns that process.
Compliance mapping
Which ISO 55001 cl.8.1 requirements does this satisfy?
The template is built against ISO 55001 cl.8.1, operational planning and control. Each section below maps to a distinct control the clause expects to see evidenced.
| Clause | Requirement | Where it lands |
|---|---|---|
| ISO 55001 cl.8.1 | Establish criteria for the operation of assets and control operation in accordance with those criteria | Compressors |
| ISO 55001 cl.8.1 | Identify asset-related risks that could affect the ability to achieve intended outcomes, including unexpected frost, ice or condenser performance | System |
| ISO 55001 cl.8.1 | Control operational activity where a loss of control could result in a significant safety or environmental consequence | Safety and integrity |
| ISO 55001 cl.8.1 | Retain documented information to the extent necessary to have confidence that operational controls are being carried out as planned | Header |
| ISO 55001 cl.8.1 | Ensure delegated operational activity, such as raising a corrective action, is controlled and its owner identified | Result |
| ISO 55001 cl.8.1 | Determine the competence of persons performing operational activity that affects asset performance and safety | Header |
What it does not cover
- A compressor reading recorded without its running or standby status, which makes a low run-hours figure impossible to interpret correctly.
- Frost or ice logged as 'expected' without checking against the defrost schedule, which can wave through an early sign of a refrigerant leak or blocked line.
- An alarm-only trip left at 'None required' for follow-up, which discards the earliest and cheapest point to intervene before a full trip.
- Ammonia detection marked healthy while a faint smell was also logged, which are two answers that should not coexist on the same entry.
- A completeness percentage below the required threshold treated as a pass, which mistakes a shift that skipped compressors for a good result.
Global
Refrigeration Plant Log requirements by country
Ammonia refrigeration plant sits under process safety regimes as well as management-system standards, and the three that carry the most weight here are different in character.
OSHA Process Safety Management, 29 CFR 1910.119
PSM applies to ammonia refrigeration above the regulated threshold quantity and requires documented operating procedures and mechanical integrity records.
This log is part of the operating discipline an OSHA inspection looks for: whether the plant actually ran within the parameters the process safety information assumes, not just whether a procedure exists on paper.
Pressure Systems Safety Regulations 2000 and COMAH where thresholds apply
PSSR requires a written scheme of examination for the pressure system; COMAH adds major-accident obligations where ammonia inventory crosses the notification threshold.
The plant log is operational evidence sitting alongside the written scheme and, where COMAH applies, supports the safety report's claim that the plant is operated within its safe envelope shift to shift.
Seveso III Directive 2012/18/EU and national ammonia codes
Seveso III governs major-accident prevention above threshold quantities; day-to-day operating standards sit in national rules, often referencing IIAR or EN 378 practice.
Where a site is a Seveso establishment, this log is the routine evidence that the safety management system's operational controls are followed in practice, not a substitute for the safety report.
How to complete it
How to complete a refrigeration plant log, step by step
The fields are simple to fill in. What decides whether the record holds up is how the attendant and reviewer handle the judgement calls the form cannot make.
Suction pressure or oil level drifting one increment outside range can be normal noise on one shift and a leading indicator over three, for that compressor reference. The record needs a stated rule for how many consecutive marginal shifts on the same unit trigger a work order.
Frost on a suction line near an evaporator is normal. Frost anywhere else is a leak, a blockage or failed insulation until proven otherwise, and the reviewer needs to see that distinction made deliberately, not assumed.
'Alarm only' and 'trip' both indicate an abnormal condition, but only one stopped the compressor. Treating an alarm-only event as routine because it did not trip the unit skips the cheaper, earlier point to intervene.
Detection equipment marked healthy is a statement about the instrument, not the atmosphere. Any smell logged alongside a healthy detector reading is a conflict needing resolution on the spot, not a pair of answers filed separately.
What auditors find
Most common refrigeration plant log findings
These are patterns that actually show up once this log is audited months into use, not theoretical failure modes.
| Finding | Clause | What fixes it |
|---|---|---|
| Suction pressure on one compressor reference trends upward across several shifts with no escalation | ISO 55001 cl.8.1 | Set an explicit rule that three consecutive marginal readings on the same compressor reference automatically raises Action Required. |
| Frost or ice is marked 'expected' on entries without reference to a defrost schedule | ISO 55001 cl.8.1 | Require defrost cycle status on the same entry as the frost question, so 'expected' cannot be selected without evidence the schedule explains it. |
| Alarm-only trip events are followed by 'Work Order Raised: Not needed' more often than trip events | ISO 55001 cl.8.1 | Treat alarm-only the same as a trip for work order purposes until root cause is confirmed benign. |
| Ammonia detection is marked healthy on the same entry as a faint smell reported | ISO 55001 cl.8.1 | Add a validation that a reported smell forces Action Required to 'Yes' regardless of the detection health field, and route it for immediate review. |
| Housekeeping in the plant room is marked 'Poor' repeatedly with no linked action | ISO 55001 cl.8.1 | Require a CAPA reference once 'Poor' repeats, since blocked emergency isolation access is a safety issue, not a tidiness one. |
| Completeness percentage is high but several compressors in a multi-unit plant have no entry that shift | ISO 55001 cl.8.1 | Calculate completeness against the number of compressor references expected on the plant, not fields answered, so a skipped unit is visible. |
Case in point
Case in point: three normal readings that were not normal together
One compressor's suction pressure rose slightly for four consecutive shifts, discharge temperature rose slightly across the same shifts, and oil level dropped from 'Yes' to 'Low' partway through. Each entry, read alone, scored within the marginal band rather than a fail, and no single shift triggered escalation.
Read together, the pattern was a refrigerant undercharge developing into a compressor running hot on reduced lubrication. The fix was a standing rule: two or more scored parameters marginal on the same compressor reference across consecutive shifts raises Action Required automatically, instead of depending on an attendant spotting the combination.
The template
The template, field by field
The form exactly as it installs. Every field, option, score and conditional rule is editable, and the links to other templates come with it.
5 sections
- Reference
- MNT-072
- Archetype
- Record
- Record ID
- RPL-2026-000
- Scoring
- Parameters in range
- Direction
- High is good
- Singleton
- Yes
- Basis
- ISO 55001 cl.8.1
- Links
- Links Refrigerant leaks, Condition monitoring
- Tags
- Utilities, Refrigeration
- Sections
- 5
- Fields
- 49
- Follow up fields
- 3
- Repeating sections
- 1
- Links out
- 4
Header
12 fieldsLog ID*
Auto sequence. Format RPL-2026-000.
The record's own ID. Other templates point at this value.
Status*
Drives who this goes to next.
- Planned2 pts
- In progress2 pts
- Complete3 pts
- Deferred0 pts
- Open0 pts
- Closed3 pts
- Overdue0 pts
Date and Time*
Completed By*
Site*
Site ID*
Format SITE-000.
Links to FDN-001 Site ID
Asset*
Asset ID*
Format AST-0000.
Links to FDN-002 Asset ID
The Trend Predicts The Failure
Suction pressure creeping up, discharge temperature creeping up, oil level dropping. Each one alone looks fine. Together they are a compressor with weeks left.
Plant Reference*
Shift*
Ambient Temperature
Compressors
Repeats12 fieldsCompressor Reference*
Running Or Standby*
Run Hours
Suction Pressure*
Discharge Pressure*
Discharge Temperature*
Oil Level Normal*
- Yes3 pts
- Low1 pt
- Very low0 pts
Oil Pressure Differential
Motor Current
Vibration Or Noise Abnormal*
- No3 pts
- Slight1 pt
- Marked0 pts
Any Alarm Or Trip*
- None3 pts
- Alarm only1 pt
- Trip0 pts
Within Operating Envelope*
- Yes3 pts
- Marginal1 pt
- No0 pts
System
6 fieldsCondenser Pressure Normal*
- Yes3 pts
- High1 pt
- Very high0 pts
Condenser Fans And Water Working*
- All3 pts
- Some1 pt
- No0 pts
Evaporator Temperatures In Range*
- Yes3 pts
- Marginal1 pt
- No0 pts
Liquid Level In Receiver Normal*
- Yes3 pts
- Low1 pt
- Very low0 pts
Frost Or Ice Where Expected Only*
Frost where there should not be frost is a leak, a blockage or a failed insulation.
- Yes3 pts
- Some unexpected1 pt
- Significant0 pts
Defrost Cycles Working*
- Yes3 pts
- Partly1 pt
- No0 pts
Safety and integrity
6 fieldsAmmonia Detection Healthy*
- Yes3 pts
- Fault indicated0 pts
Any Smell Of Ammonia*
- No3 pts
- Faint0 pts
- Strong0 pts
Leak Record ID
Links to ENV-021 Register ID
Machinery Room Ventilation Running*
- Yes3 pts
- Intermittent1 pt
- No0 pts
Emergency Isolation Accessible*
- Yes3 pts
- Difficult1 pt
- No0 pts
Housekeeping In Plant Room*
- Good3 pts
- Acceptable1 pt
- Poor0 pts
Result
13 fieldsItems Assessed*
Excludes anything marked N/A.
Items Failed*
Score Percent*
Calculated on submission. High is good. N/A items leave the denominator.
Result Band*
- Pass3 pts
- Caution1 pt
- Fail0 pts
Completeness Percent*
How much of the template was actually answered. A high score on a half completed form is not a high score.
Action Required*
Raise the action record, then enter its reference here.
- No2 pts
- Yes0 pts
Priority
- High0 pts
- Medium1 pt
- Low3 pts
CAPA ID
Format CAPA-2026-00000.
Links to FDN-014 CAPA ID
Action Owner
Plant Attendant*
Signature*
Engineering*
Second Signature*
MNT-072 · record IDs look like RPL-2026-000 · Links Refrigerant leaks, Condition monitoring
Open in KnowellaRun it with agents
From a document you fill in to a programme that runs itself
The form is the easy part. Reading the trend across shifts, catching two marginal readings before they become one failure, and holding the evidence together is the work that actually slips.
Holds the plant log against the asset register, tracks suction pressure, discharge temperature and oil level per compressor across shifts, and flags a combination trend before any single reading would.
Keeps ammonia detection health, reported smells and ventilation status visible together, so a process safety or COMAH review can be answered from one place, not reconstructed after the fact.
Links a logged refrigerant leak indication through to the environmental aspects register, so a frost or ammonia finding does not stall between systems.
Rolls shift completion and exceptions into one view across the plant room, and holds every escalation for your approval before it touches a live record.
This template lives in KnowMaintain — asset maintenance. Work orders, planned maintenance, calibration, reliability and shutdowns.
Meet KnowMaintain→Glossary
Refrigeration Plant Log definitions and key terms
- Suction pressure
- The pressure of refrigerant vapour entering the compressor. A falling suction pressure at stable load often points to a restriction or reduced refrigerant charge.
- Discharge temperature
- The temperature of refrigerant vapour leaving the compressor. Rising discharge temperature alongside normal pressures often indicates reduced lubrication or a mechanical fault developing.
- Operating envelope
- The combined range of pressures and temperatures a compressor is designed to run within for a given refrigerant and load, as distinct from any single parameter looking acceptable on its own.
- Machinery room ventilation
- The forced ventilation system that clears refrigerant vapour from the compressor room in the event of a leak, required to be running and unobstructed for ammonia systems.
- Defrost cycle
- The scheduled process that clears ice buildup from evaporator coils. Frost appearing outside the defrost schedule or in unexpected locations usually indicates a fault rather than normal operation.
FAQ
Frequently asked questions about refrigeration plant log
Who fills in the refrigeration plant log?+
The plant attendant on shift, at the plant, each round. It is not intended to be reconstructed at the end of a shift from memory.
How often should entries be made?+
Each shift, day, afternoon and night. The compressors section is built to repeat for every compressor reference on the plant, each round.
Does one healthy compressor reading mean the plant passed?+
No. Every compressor reference on the plant needs its own entry, and the system and safety sections are read alongside them; one clean compressor sitting next to an unescalated marginal one on another unit is not a pass.
What happens when Action Required is marked 'Yes'?+
A CAPA reference and action owner become required fields, tying the shift entry to a specific corrective action rather than leaving the issue implicit in a low score.
Why does the log include an ammonia smell question separate from the detector reading?+
Because a slow leak can sit below the fixed detector's alarm threshold for a period. Asking the attendant directly catches what the instrument has not yet triggered on.
Can this template be adjusted for a specific refrigeration plant?+
Yes. Every field, range and score is editable, and most sites install it as shipped, run it for a full season, then tighten the ranges against their own baseline.
Keep going
Related templates and programmes
Industries this is written for
Programmes this belongs to
Used together in Pressure Systems and Refrigeration
Refrigeration Contractor Verification
Verifies refrigeration contractor certification, ammonia competence, emergency capability and out of hours response
Environmental Aspects Register
Lists how your activities interact with the environment and how significant each interaction is
Refrigeration Unit Service Record
Records service and performance testing of a transport refrigeration unit, including temperature pull down and refrigerant
Boiler Operation Record
Records boiler operating parameters, water treatment results and blowdown through a shift
Water Treatment Record
Records dosing, testing and results for boiler, cooling and process water systems
Legionella Control Record
Records temperature checks, flushing, sampling and cleaning across water systems that can generate aerosols
More in Utilities
Boiler Operation Record
Records boiler operating parameters, water treatment results and blowdown through a shift
Water Treatment Record
Records dosing, testing and results for boiler, cooling and process water systems
Legionella Control Record
Records temperature checks, flushing, sampling and cleaning across water systems that can generate aerosols
Steam Trap Survey
Surveys steam traps for failed open and failed closed condition, with the energy cost of each failure
Emergency Generator Test Record
Records the periodic run and load test of standby generation, with fuel, coolant and transfer performance
Uninterruptible Power Supply Check
Checks battery condition, autonomy and transfer on systems protecting controls, chillers or data
Written and reviewed by
Siddarth Singh
Founder & Chief Executive Officer, Knowella
Certified Safety Professional and industrial and systems engineer with more than a decade inside food supply chain, freight and manufacturing operations. This page was written against the current text of the standards it cites, not against secondary summaries of them.
- Certified Safety Professional (CSP), Board of Certified Safety Professionals
- MBA, University of Chicago Booth School of Business
- MS and BS, The Ohio State University, Industrial and Systems Engineering
- Six Sigma Black Belt
Sources and last review. Reviewed 16 August 2026 against:
- ISO 55001 cl.8.1 — Operational planning and control
- OSHA Process Safety Management, 29 CFR 1910.119
- Pressure Systems Safety Regulations 2000 (UK)
- Seveso III Directive 2012/18/EU
This page is general guidance, not legal advice. Confirm requirements with your jurisdiction’s regulator.