What this is
What is a steam trap survey?
What is a steam trap survey?
It is a systematic inspection of every trap in a steam and condensate system to establish which are working, which have failed open and which have failed closed, with an estimate of the steam and money each failure costs. It produces an energy figure and a maintenance backlog, and its value depends on the second being acted on.
What is the difference between failed open and failed closed?
A failed open trap passes live steam continuously into the condensate return, wasting energy but causing no process complaint, which is why it persists for years. A failed closed trap holds condensate in the steam space, causing waterhammer, poor heat transfer and freeze risk. One is an energy loss, the other a safety issue.
What does an ultrasonic survey actually detect?
It listens to the acoustic signature of flow through the trap, distinguishing intermittent discharge from continuous blow-through. That is more discriminating than temperature methods, because a trap can be at the right upstream temperature and still leak steam. It also requires the surveyor to know the trap type, since a thermodynamic and a float trap sound different when healthy.
Scope
When is a steam trap survey required?
This survey covers the condition and energy cost of the trap population. It is not the boiler log, the water treatment record or the steam system safety check. Keeping them apart matters because this is an annual energy exercise with a maintenance output, while the others are operational records.
Use this template when
- The annual survey of the full trap population is due, or a system has never been surveyed
- An energy review under ISO 50001 has identified the steam system as a significant energy use
- Steam consumption has risen with no corresponding change in production output
- Waterhammer, wet steam or heating shortfalls suggest failed closed traps on a header
- A capital case for a replacement programme needs a baseline of failure rate and cost
Do not use it for
- Boiler Operation Record, which captures operating parameters and blowdown through a shift rather than the condition of the distribution system
- Steam System Safety Check, which covers guarding, insulation, relief and isolation as a safety matter, not trap efficiency
- Water Treatment Record, which holds boiler and condensate chemistry, where a contaminated return from failed traps is evidenced
- Pressure System Written Scheme, which defines the statutory examination regime and is not satisfied by an energy survey
- Environmental Aspects Register, which records the aspect and its significance rather than the measurements produced here
Compliance mapping
Which ISO 50001 cl.9.1 requirements does this satisfy?
This is primarily an ISO 50001 instrument, supporting the energy review and the indicators that follow from it. Where the steam system is a relevant pressure system, the national maintenance duty also applies, because a failed closed trap is a waterhammer risk.
| Clause | Requirement | Where it lands |
|---|---|---|
| ISO 50001:2018, cl.6.3 | The energy review must identify significant energy uses and the opportunities for improving performance in them. | Header |
| ISO 50001:2018, cl.6.6 | The organisation must plan how energy data is collected, including what is measured and by what method. | Header |
| ISO 50001:2018, cl.7.2 | Persons doing work affecting energy performance must be competent on the basis of education, training or experience. | Header |
| ISO 50001:2018, cl.6.4 | Energy performance indicators must be appropriate for measuring performance and capable of update. | Summary |
| ISO 50001:2018, cl.9.1 | Energy performance and system effectiveness must be monitored, measured, analysed and evaluated at planned intervals. | Summary |
| ISO 50001:2018, cl.7.5 | Documented information necessary for energy performance must be maintained and controlled. | Summary |
| ISO 50001:2018, cl.6.2 | Objectives and energy targets require action plans stating what will be done, by whom, by when and how evaluated. | Result |
| Pressure Systems Safety Regulations 2000, reg.12 | The user must ensure the pressure system is properly maintained in good repair so as to prevent danger. | Traps surveyed |
What it does not cover
- A headline annual saving with no work order references, which means no failure has entered the maintenance system and the population will be resurveyed unchanged.
- Traps Not Located left at zero on an unreconciled register, which means the failure rate is calculated against a denominator nobody has verified.
- Visual on discharge used across the whole system, which means blow-through on a healthy looking discharge was never detectable and the count is low.
- Repeat Failure At This Point answered No by default on every row, which means the previous survey was never consulted and installation faults are repaired as new.
- Estimated Annual Cost taken from a default rate rather than site fuel price, which means the business case rests on a figure finance will reject on sight.
Global
Steam Trap Survey requirements by country
Trap surveys are rarely mandated by name. They surface as the evidence expected under mandatory energy audit regimes, which is where the three instruments below matter.
Energy Efficiency Directive (EU) 2023/1791, Article 11
Undertakings above defined consumption thresholds must implement an energy management system, or undergo an audit where they do not.
Where a site runs steam, an auditor expects the distribution system to have been assessed, not just the boiler. A dated survey with a failure rate and a costed action plan discharges that directly.
Energy Savings Opportunity Scheme Regulations 2014 (SI 2014/1643)
Large undertakings must carry out periodic audits covering total energy consumption and identify cost effective savings.
Trap losses are among the most frequently cited ESOS recommendations and the most frequently unimplemented. Work Order ID and Action Required let you show implementation rather than repeated identification.
40 CFR Part 63 Subpart DDDDD, boiler and process heater standards
Affected facilities must complete a one time energy assessment covering the boiler and the systems it serves, including steam distribution.
Because the assessment reaches downstream of the boiler, a trap survey is the practical evidence for the distribution element. Holding it as a structured record rather than a contractor PDF keeps it retrievable on review.
How to complete it
How to complete a steam trap survey, step by step
The survey is straightforward to walk. Four judgements decide whether it is worth anything twelve months later.
Survey Method is scored because the methods are not equivalent. Ultrasonic separates continuous blow-through from normal intermittent discharge. Thermal imaging finds failed closed reliably but is weaker on failed open. A temperature probe tells you the trap is hot, which a leaking trap also is. Choosing the weakest method and reporting a low failure rate produces a reassuring, useless record.
Traps In System, Traps Surveyed and Traps Not Located are three separate numbers deliberately. Calculate the failure rate against what was actually surveyed and carry the not located count alongside as a stated limitation. Where Register Updated is No, next year inherits the same blind spot, so trace and correct first.
A trap failing in consecutive surveys usually means an undersized trap, excessive back pressure in the return, a blocked strainer, or a type wrong for the duty. Replacing like for like gives the same result next year. Where Repeat Failure At This Point is Yes, raise an installation review, not a replacement job.
Estimated Steam Loss and Estimated Annual Cost drive the business case, so the assumptions must be recorded. Use the site fuel price and the real operating hours for the header, not a generic annual figure. A claimed saving on a line that runs eight weeks a year is discredited in one meeting, and takes the credible findings with it.
What auditors find
Most common steam trap survey findings
These recur across almost every first survey, with the clause each bears on.
| Finding | Clause | What fixes it |
|---|---|---|
| Survey completed and reported, no work orders raised against any failed trap. | ISO 50001:2018, cl.6.2 | Require a Work Order ID on every row whose Condition is not Working before sign off. |
| Failure rate reported without stating how many traps could not be located. | ISO 50001:2018, cl.9.1 | Publish Traps Not Located alongside the rate and treat reconciliation as an action in its own right. |
| Whole system surveyed by temperature probe because ultrasonic kit was absent. | ISO 50001:2018, cl.6.6 | Record the method honestly and mark the survey as partial coverage rather than complete. |
| Same trap references appear as failed in three consecutive annual surveys. | ISO 50001:2018, cl.6.3 | Answer Repeat Failure At This Point from the previous record and escalate those points to a sizing review. |
| Survey carried out by an untrained operative with no reference trap signatures. | ISO 50001:2018, cl.7.2 | Record Surveyed By accurately and treat Untrained as invalidating the count until re-checked by a competent surveyor. |
| Failed closed traps on outdoor lines left on the backlog through winter. | Pressure Systems Safety Regulations 2000, reg.12 | Separate failed closed from failed open in prioritisation, since the first is a waterhammer and freeze risk. |
Case in point
Case in point: the survey bought four years running
A dairy processing site commissioned an annual trap survey from the same contractor for four consecutive years. Each report gave a failure rate between eleven and fourteen per cent and an annual loss of roughly two hundred thousand pounds. The reports went to the energy committee, were cited in the ISO 50001 management review, and were filed. No replacement budget was ever raised.
Comparing the fourth report line by line with the first, sixty one of the failed tags were identical. The site had been paying to re-identify the same failures. Eleven had been replaced at some point and failed again, pointing to a back pressure problem on one return header that no survey had been asked to look at. The change was procedural: each failed row had to carry a work order reference before sign off, and repeat failures went to an installation review. The next year's failure rate was under four per cent.
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.
4 sections
- Reference
- MNT-075
- Archetype
- Inspection
- Record ID
- STS-2026-000
- Scoring
- Failed traps
- Direction
- Low is good
- Singleton
- Yes
- Basis
- ISO 50001 cl.9.1
- Links
- Links Ultrasonic, Energy initiatives
- Tags
- Utilities, Steam
- Sections
- 4
- Fields
- 41
- Follow up fields
- 3
- Repeating sections
- 1
- Links out
- 3
Header
10 fieldsSurvey ID*
Auto sequence. Format STS-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
More Wasted Energy Than Every Lighting Project
A single failed open trap can vent hundreds of kilograms of steam a day. Most sites have never surveyed them and have no idea how many are gone.
Survey Method*
Ultrasonic, thermal imaging, temperature probe or visual on discharge.
- Ultrasonic4 pts
- Thermal imaging3 pts
- Temperature probe2 pts
- Visual on discharge1 pt
Surveyed By*
- Specialist contractor3 pts
- In house trained3 pts
- Untrained0 pts
Traps In System*
Traps surveyed
Repeats9 fieldsTrap Reference*
Location*
Trap Type
Condition*
Working, failed open, failed closed, leaking, or blocked.
Estimated Steam Loss
Estimated Annual Cost
Priority*
- High0 pts
- Medium1 pt
- Low3 pts
Work Order ID
Links to MNT-002 Work Order ID
Repeat Failure At This Point*
- No3 pts
- Yes0 pts
Summary
9 fieldsTraps Surveyed*
Traps Working*
Failure Rate Percent*
Above ten percent is common on unsurveyed sites and is entirely avoidable.
Failed Open*
Failed Closed*
Failed closed traps cause waterhammer and freeze risk, which is a safety issue as well as an energy one.
Total Estimated Annual Loss*
Traps Not Located*
Register Updated*
- Yes3 pts
- No0 pts
Feeds Energy Initiative*
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
Surveyor*
Signature*
Engineering Manager*
Second Signature*
MNT-075 · record IDs look like STS-2026-000 · Links Ultrasonic, Energy initiatives
Open in KnowellaRun it with agents
From a document you fill in to a programme that runs itself
The survey takes a day. What slips is everything after it: the work orders, the register correction and the repeat failure pattern.
Turns each failed row into a work order against the trap tag, carries the previous survey forward so Repeat Failure At This Point is answered from data, and keeps the register reconciled.
Consumes the failure rate and total loss as an energy performance indicator, feeds the survey into the energy review, and holds the improvement action plan.
Picks up failed closed findings as a waterhammer and freeze risk rather than only an energy cost, and links them to the pressure system maintenance duty.
Compares this survey against the previous one tag by tag, surfaces the points failing repeatedly, and holds every write for approval before it touches a record.
This template lives in KnowMaintain — asset maintenance. Work orders, planned maintenance, calibration, reliability and shutdowns.
Meet KnowMaintain→Glossary
Steam Trap Survey definitions and key terms
- Steam trap
- An automatic valve that discharges condensate and non-condensable gases while holding back live steam. It fails open, closed, leaking or blocked.
- Failed open
- A trap passing live steam continuously into the condensate return. It causes no process complaint, which is why it persists, and it is the dominant energy loss.
- Failed closed
- A trap holding condensate in the steam space. It reduces heat transfer and creates waterhammer and freeze risk, so it carries a safety consequence too.
- Blow-through
- The continuous acoustic signature of steam passing through a failed trap, distinguishable by ultrasonic survey from the intermittent discharge of a healthy one.
- Energy performance indicator
- A quantitative measure of energy performance under ISO 50001. Trap failure rate works well because it is comparable between years and independent of fuel price.
FAQ
Frequently asked questions about steam trap survey
How often should the trap population be surveyed?+
Annually for the full population is the usual position, since failure rates of around five per cent a year are typical. Higher pressure, heavy cycling or a known back pressure problem justify a shorter cycle, and repeat failure points should be re-checked sooner.
Is a specialist contractor necessary?+
Not necessarily, but the competence is. Reading an ultrasonic signature means knowing what a healthy thermodynamic, float or inverted bucket trap sounds like on that duty. Record In house trained only where the training is evidenced, and benchmark the first such survey against a contractor sample.
Why record trap type if it is optional?+
Because failure mode correlates strongly with type and duty. Thermodynamic traps on low pressure or high back pressure duties fail open predictably, and inverted bucket traps lose their prime on superheat. Recording type turns a list of failures into a pattern that can be designed out.
How should the estimated saving be calculated?+
From orifice size, differential pressure and the real operating hours for that line, priced at site fuel cost. Generic per-trap figures overstate losses on intermittent lines and understate them on high pressure headers, and either error discredits the survey.
Why is this template a singleton?+
One current record per workspace holds the standing position of the trap population, which other records refer back to. Each annual survey supersedes the last, while its repeating rows preserve the trap by trap history the repeat failure judgement depends on.
Can the template be changed?+
Yes. Fields, options, scores and conditional rules are editable, and the links to the ultrasonic and energy initiative records come with it. The most common change is making Work Order ID mandatory on any row whose Condition is not Working, which stops the survey becoming a report with no consequence.
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
Refrigeration Plant Log
Records suction and discharge pressures, temperatures, oil levels and run hours across the refrigeration plant
Water Treatment Record
Records dosing, testing and results for boiler, cooling and process water systems
More in Utilities
Boiler Operation Record
Records boiler operating parameters, water treatment results and blowdown through a shift
Refrigeration Plant Log
Records suction and discharge pressures, temperatures, oil levels and run hours across the refrigeration plant
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
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 50001:2018, Energy management systems, cl.6.2 to cl.6.6, cl.7.2, cl.7.5 and cl.9.1
- Energy Efficiency Directive (EU) 2023/1791, Article 11, energy management systems and audits
- Energy Savings Opportunity Scheme Regulations 2014 (SI 2014/1643)
- Pressure Systems Safety Regulations 2000 (SI 2000/128), reg.12, maintenance
- 40 CFR Part 63 Subpart DDDDD, industrial boiler standards, energy assessment requirement
This page is general guidance, not legal advice. Confirm requirements with your jurisdiction’s regulator.