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Every year, we service and calibrate our own kit because doing things right starts with the tools we use.

What We Calibrate

We recently received back a batch of essential kit from its annual service and calibration, including:

• Torque wrenches
• Torque screwdrivers
• Pressure gauges
• Rotating vane anemometers
• Manometers
• Hot wire anemometers
• Portable Appliance Testers (PAT)

Each item is returned with supporting calibration certification and records, helping us maintain clear evidence of when the equipment was checked and when it is next due.

Why It Matters for You

When we test or inspect your systems, the accuracy and condition of our equipment matter. That’s why our measurement equipment is regularly serviced and calibrated, with records maintained to support the readings included in our reports.

Using properly calibrated tools supports:

• Accurate and consistent measurements
• Reliable reports and certificates
• Clear evidence of equipment maintenance and calibration
• Better-supported records for audits, insurers and internal compliance reviews

A Culture of Compliance

The same standards we apply on client sites also guide how we run our own operations, from record-keeping to equipment servicing.

Annual equipment calibration is one part of how Velocity Safety maintains professionalism, consistency and technical confidence across its inspection and testing services.

We’ve all seen fire point stands at outdoor sites telling people to “leave the building” – even when there isn’t one. At Velocity Safety, we think compliance should be smarter than that.

Built for Real Sites – Not Just the Checklist

Our fire point stands are custom-built for real-world conditions. Instead of flatpacks and guesswork, we handle the whole process from start to finish:

• We assemble your stand on-site – so you don’t have to build it.
• We apply all vinyl signage professionally – including any custom fire action signs.
• We bolt the cabinets securely for long-term durability.
• We offer wireless or standalone alarms depending on your site needs.
• We label and commission the extinguishers properly – our services covers everything from fire extinguisher installation to compliance audits.
• We individually number each extinguisher for full traceability.
• We even brand the stands with your company logo.

These stands are already being used on projects across Manchester, Gloucester, Bristol, and Essex – fully assembled, labelled, and delivered ready to go.

Why We Designed a Scaffold Fire Point Stand

We kept seeing the same problem on large scaffolding structures: fire extinguishers were often left on the ground floor, positioned inside the building, or placed too far away from where operatives were actually working.

On many sites, call points and extinguishers are not within a practical 30 metre travel distance. In a high-risk industry, that is not something we think should be accepted as normal.

The problem was simple: the usual options were not designed for scaffolding. Standard trolleys, plastic stands and tubular stands can create falling object hazards, trip hazards, stability issues, or leave extinguishers exposed to damage.

Damaged extinguishers often end up being condemned, which turns poor fire point setup into a repeated cost problem as well as a safety issue.

That is why Velocity Safety developed a purpose-built scaffold fire point stand designed to fit directly to standard scaffolding tube or 48.3mm key clamp handrail and guardrails using the supplied fittings.

For real solutions to real problems, do not just buy online and hope for the best.

Fire Point Scaffold Stand Features

• Designed for scaffolding: Fits directly to standard scaffold tube or 48.3mm key clamp handrails and guardrails.
• Supplied fully assembled: No flatpack setup or site guesswork required.
• Made in Blackburn, UK: Built from a 2mm tube frame and powder coated for durability.
• Custom signage available: Including branded fire action signage and site-specific instructions.
• Choice of extinguishers: Including P50 options where suitable.
• Commissioning available: Extinguishers can be properly commissioned before being placed into service.
• Alarm options: Choose from standalone alarms or interlinked wireless alarms depending on site requirements.

Designed for Construction, Civils, and Groundworks Sites

Whether you’re mobilising a new construction site, managing utilities projects, or overseeing civil engineering work, we’ll help you stay compliant without the hassle of flatpack stands and ad-hoc equipment.

Cold Weather Considerations

Did you know most fire extinguishers stop working properly below 5°C? That could be a problem as winter rolls in – especially for outdoor sites, events, and groundworks projects.

Ready for Your Next Project?

If you’re preparing for your next project or site mobilisation, our scaffold fire point stands help keep extinguishers, alarms and emergency equipment accessible throughout the build. We’ll also make sure your fire safety equipment is properly set up, branded and ready to go, and dispose of any old or unused extinguishers in line with environmental regulations.

Every site is different – but the goal is always the same: deliver full compliance with minimal disruption. Here’s a recent Friday job from the Velocity Safety team.

Supporting On-Site Safety Without Disruption

We headed to a client site at the other end of the country, deliberately scheduled on a Friday – their quietest day of the week. It’s a small adjustment that helps minimise business disruption while we carry out a full compliance check.

What We Serviced

• Gas monitor calibrations
• Tripods
• Fall arrest blocks
• Winches
• Harnesses (Explore our Work at Height and Fall Arrest Equipment Servicing)
• A few stray fire extinguishers and CAT & Genny kits

Why Our System Works

We’ve worked with this client for over 12 months – and part of that relationship has involved getting their van kit properly organised. Every item is labelled by vehicle reg plate, so the client knows exactly where each piece of equipment belongs. It’s a small touch that helps keep inspections running smoothly.

Need End-to-End Support?

Whether it’s confined space kit, fall arrest equipment, or just making sure your gear is labelled and trackable – we’ll help you stay compliant and organised without the hassle.

“A HEPA filter can be the correct grade and still leak after it has been installed.”

A filter’s manufacturer rating describes the filter element under defined test conditions. It does not, by itself, show that the installed system has no leaks around the filter, its seals or its housing.

DOP testing is the common name for an in-situ integrity test that checks the installed HEPA or ULPA filtration system for leakage.

This guide explains what the term means, how the test works, when it may be needed and what the resulting report should tell you.

Explore Velocity Safety’s DOP, PAO and HEPA filter integrity testing service.

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What Is DOP Testing?

DOP testing checks an installed HEPA or ULPA filter system for leaks. It is commonly used where filtered air is important to contamination control, worker protection or the performance of a process.

A test aerosol is introduced into the airflow before the filter. The engineer checks the downstream side using an appropriate calibrated instrument to find any aerosol passing through or around the installation.

Depending on the system and test method, leakage may be found at:

• The filter media
• The seal or gasket between the filter and its frame
• The filter frame or its seating
• Joints and penetrations in the housing
• Other routes that allow air to bypass the filter

This is why a new, correctly classified filter can still fail an in-situ integrity test if it has been damaged or installed incorrectly.

A DOP or PAO integrity test should not be presented as a complete manufacturer efficiency-classification test. It answers a different question: is the installed filtration system leaking?

What Does DOP Test Stand For?

DOP originally stood for dioctyl phthalate, the substance historically used to produce the aerosol challenge for this type of test.

The name has remained familiar across the industry even though another suitable aerosol is often used today. You may also hear people describe the procedure as a dispersed oil particulate test, PAO test, HEPA integrity test or installed filter leak test.

Those terms can point to the same general purpose, but they do not identify the exact aerosol, instrument, test method or acceptance criteria. Those details should be confirmed for the particular system.

Is DOP Testing the Same as PAO Testing?

They usually refer to the same type of in-situ filter integrity assessment, but DOP and PAO are not the same substance.

PAO means polyalphaolefin. It can be used to create the upstream aerosol challenge. Other suitable test aerosols, including Ondina products, may also be used according to the equipment and procedure.

If a contractor or site specification asks for a “DOP test”, confirm:

• Which aerosol will actually be used
• Which equipment and method are appropriate
• Whether the filter can be challenged safely upstream
• How the downstream side will be accessed and checked
• Which acceptance criteria apply

The name of the test alone is not enough to define its complete scope.

How Does a DOP or PAO Filter Integrity Test Work?

The exact procedure depends on the filter system and applicable method. A typical in-situ aerosol test follows these stages:

Not every installation permits the same downstream scan or sampling arrangement. The engineer should identify any limitations in the report rather than imply that an inaccessible part of the system has been fully examined.

What Are the HEPA Filter Integrity Test Acceptance Criteria?

There is no single percentage that should be quoted as the universal pass/fail limit for every in-situ HEPA or ULPA installation.

The applicable criterion depends on the filter class, the installation, the test method, relevant standard and the facility’s requirements. For example, a cleanroom validation programme may refer to BS EN ISO 14644-3, while a different industrial filtration application may require another appropriate method.

The criterion should be agreed before the test and stated on the report. The result should then make clear whether each tested filter system met that criterion and where any leakage was found.

A filter’s factory efficiency rating and an installed-system leakage result are related, but they should not be treated as interchangeable measurements.

When Should You Book a DOP Test?

An integrity test may be appropriate:

• After installation: To check that a new filter and its housing have been installed without unacceptable leakage.
• After filter replacement: To identify damage or a poor seal before relying on the replacement.
• After repairs or relocation: Where work could have affected the filter, frame or housing.
• After suspected damage or a performance change: Where there is a reason to question containment or filtration.
• During a planned validation or examination programme: At an interval appropriate to the system, application and risk.

Do not apply “every six months” or “every 6–24 months” to every HEPA filter without considering its application. The required interval may come from the site’s validation programme, manufacturer instructions, risk assessment, contract specification or other applicable guidance.

Where a HEPA filter forms part of a local exhaust ventilation system used to control exposure under COSHH, its integrity test may be coordinated with the wider LEV thorough examination and test. That does not make a DOP test identical to a full LEV examination.

What Equipment Can Be DOP or PAO Tested?

Velocity Safety provides in-situ integrity testing for suitable HEPA and ULPA filtration systems, including applications such as:

• Cleanrooms and controlled environments
• Negative pressure units and air scrubbers
• HEPA-filtered dust extraction equipment
• Filters within suitable LEV systems
• Spray booths and process extraction systems
• Laboratory and healthcare filtration systems
• Suitable portable extraction units

Whether a particular unit can be tested using an aerosol challenge depends on its design, airflow, safe upstream injection and downstream access. An L-, M- or H-class label alone does not establish that a specific portable extractor contains an accessible HEPA filter suitable for this method.

If you are unsure about your equipment, provide its make, model, filter details and photographs when enquiring. Velocity Safety can confirm the practical test arrangement.

What Problems Can an Integrity Test Find?

An installed filter may leak because:

• The filter media has been damaged during handling or use
• A gasket is missing, compressed unevenly or incorrectly seated
• The filter is the wrong size for its housing
• The frame or housing has been damaged
• A joint or penetration allows air to bypass the filter
• Repairs or filter replacement have disturbed the installation

Finding the location matters. The appropriate remedy may be to reseat the filter, repair a seal or housing, or replace the filter. The system should then be re-tested as appropriate before the result is treated as resolved.

What Should a DOP Test Report Include?

A useful report should identify what was actually tested and how the result was reached. Depending on the system and method, it may include:

• The site, equipment and filter identification
• The test date and location
• The aerosol used
• The instrument and its calibration details
• The test procedure and agreed acceptance criteria
• The upstream challenge conditions or concentration
• Downstream readings or scan results
• Any leakage location and its measured result
• Pass or fail outcome and any test limitations
• Recommended remedial action and re-test result, where applicable

The report should not simply state “passed” without making the tested equipment, method and acceptance criterion clear.

Final Takeaway

A DOP test checks whether an installed HEPA or ULPA filtration system has unacceptable leakage. It can find faults in the filter media and around the seals, frame and housing that a filter’s manufacturer rating cannot rule out.

The correct aerosol, test method, pass/fail criterion and interval depend on the installation. Establish these before testing and retain the report as part of the system’s maintenance or validation records.

Frequently Asked Questions

What does DOP stand for?

DOP originally referred to dioctyl phthalate, the substance historically used to create an aerosol for filter testing. The phrase “DOP test” remains common even when a different aerosol is used.

Is DOP testing the same as PAO testing?

They commonly describe the same general type of in-situ filter integrity test, but DOP and PAO are different substances. Ask which aerosol and test method will actually be used.

Is a DOP test the same as testing HEPA filter efficiency?

No. An in-situ integrity test looks for leaks in the installed filter and its surrounding assembly. A manufacturer’s efficiency or classification test measures the filter element under a defined procedure.

Is DOP testing legally required in the UK?

There is no blanket legal rule requiring a DOP test for every HEPA filter. Where filtration is part of an engineering control for hazardous substances, COSHH requires appropriate maintenance and examination of the control. An integrity test may be needed to demonstrate that the particular system remains effective.

How often should a HEPA filter be DOP tested?

There is no universal interval for every installation. Follow the applicable validation programme, risk assessment, manufacturer instructions and relevant standards. Testing should also be considered after installation, replacement, damage or repairs that could affect integrity.

Does a new HEPA filter need an integrity test?

Where the installation needs verified containment or cleanroom performance, testing after installation can reveal damage or leakage around the filter that a factory classification would not detect.

What happens if a filter fails?

The leak location and result should be recorded. The filter may need reseating or replacement, or the seal or housing may need repair. The affected system should be re-tested as appropriate after the remedial work.

Will I receive a report?

Yes. Velocity Safety supplies a traceable report identifying the tested system, procedure, results, outcome and any defects or recommended remedial action.

Resources & Further Guidance

• • COSHH Regulation 9 – Maintenance, Examination and Testing of Control Measures
  • HSE HSG258 – Controlling Airborne Contaminants at Work
  • ISO 14644-3:2019 – Cleanroom Test Methods
  • BSI – Guide to In-Situ High-Efficiency Filter Leak Testing

 

Discover how Pendulum Slip Testing measures real-world floor safety – and what your PTV score actually means.

The Pendulum Slip Test (also known as the British Pendulum Test) is the UK’s HSE-preferred method for measuring slip resistance under wet or dry conditions. It provides a precise Pendulum Test Value (PTV) that tells you whether a floor surface meets accepted safety standards.

Used in workplaces, public buildings, and legal investigations, it’s the only test recognised by HSE guidance, UK Slip Resistance Group (UKSRG), and BS 7976-2 / BS EN 16165.

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What is Pendulum Slip Testing?

Pendulum slip testing is also commonly called the British Pendulum Test, pendulum test, PTV test or floor slip test. These terms usually refer to the same method of measuring slip resistance using a pendulum tester.

Pendulum testing uses a swinging arm fitted with a rubber slider (Slider 96 for footwear, Slider 55 for barefoot) to simulate a heel striking the floor.

As the slider contacts the surface, it loses momentum – the distance travelled after impact determines the Pendulum Test Value (PTV).

This method is:

• Accepted by the HSE and UK Slip Resistance Group (UKSRG)
• Reliable in both wet and dry conditions
• Admissible in court to demonstrate duty of care and risk mitigation

Pendulum testing is used in:

• Workplaces, retail, and commercial environments
• Public buildings and leisure centres
• Insurance claims and post-incident investigations

How Does the Test Work?

Pendulum testing is carried out using a Pendulum Skid Resistance Tester, a precise mechanical device approved by the HSE. The process simulates a heel strike under realistic walking conditions.

Here’s a quick overview of how the test is performed:

1. A Pendulum Tester is set up on-site with a calibrated slider
2. The slider swings down and strikes the surface
3. The arm continues moving and stops – a needle records the PTV
4. Tests are carried out:
   • Wet and dry
   • With and across foot traffic direction
   • In multiple zones where relevant

To ensure results are accurate and representative, testing is conducted:

• In multiple directions (with/across/diagonal to foot traffic)
• On both dry and wet surfaces
• Using a certified and calibrated device operated by trained technicians

When performed correctly, pendulum testing offers a highly repeatable, legally defensible measure of slip resistance – suitable for use in court, insurance claims, or compliance audits.

What is a Good PTV Score?

After a pendulum test, you’ll receive a Pendulum Test Value (PTV) — this number indicates how slippery a surface is. The HSE and UKSRG classify these scores into three risk bands:

PTV Score	Slip Risk	Typical Interpretation
0–24	🔴 High risk	Likely to fail safety requirements
25–35	🟠 Moderate risk	Caution required; may need mitigation
36+	🟢 Low risk	Meets HSE guidance for safe flooring

A PTV of 36 or higher is considered the UK benchmark for low slip risk, even in wet conditions. Surfaces scoring below 24 are regarded as high risk, especially when exposed to contaminants like water, oil, or food – and are often referenced in legal claims as evidence of foreseeable hazard.

These thresholds are not arbitrary; they are standard across HSE guidance, UKSRG testing protocols, and civil litigation.

What Does PTV Mean?

PTV stands for Pendulum Test Value. It is the score recorded by the pendulum tester after the rubber slider passes across the floor surface.

The higher the PTV, the greater the slip resistance. A score of 36 or above is generally considered low slip risk in UK guidance. Scores between 25 and 35 indicate moderate risk, while scores below 24 indicate high slip risk.

Is Pendulum Testing a Legal Requirement?

The test itself is not named in law, but your legal duty to assess and control slip risks absolutely is.

Applicable legislation:

• Health and Safety at Work etc. Act 1974
• The Management of Health and Safety at Work Regulations 1999
• The Workplace (Health, Safety and Welfare) Regulations 1992

Under these laws, you must:

• Identify slip risks as part of your general risk assessment
• Take reasonably practicable steps to prevent them
• Maintain safe access and flooring

🧾 Pendulum testing is the most widely accepted way to demonstrate you’ve taken reasonable precautions – and is routinely used in court, insurance disputes, and HSE investigations.

How Often Should Pendulum Testing Be Carried Out?

The HSE doesn’t specify an exact interval, but floor surfaces should be re-tested whenever their condition changes or if a slip incident occurs. In most workplaces, annual testing is advised – more frequently for high-traffic or wet areas such as entrances, kitchens and pools.

• Every 12 months – routine verification for most floors
• Every 6 months – wet areas or where contaminants are common
• Immediately – after floor treatment, cleaning change or incident

Regular testing provides ongoing proof of due diligence and reduces liability in the event of a slip claim or audit.

HSE Standards & British Guidance

Pendulum testing is backed by:

• BS 7976-2 – The British Standard for slip resistance using the pendulum
• BS EN 16165 – European standard for testing slip resistance of surfaces
• UKSRG Guidelines Issue 6 (2024) – In-situ floor testing framework, endorsed by the HSE

Compared to lab tests like the R-rating ramp test, pendulum testing:

• ✅ Is performed on-site, in real-world conditions
• ✅ Accounts for contaminants like water, oil, and food
• ✅ Is legally admissible in court

Wet vs Dry Testing Conditions

Floors must be safe under the conditions they are actually used in. The wet test is often the most critical, since most slips occur on contaminated or damp surfaces. Pendulum testing provides separate PTV scores for each condition.

Condition	Typical PTV Range	Risk Rating	Example Environments
Dry	50–70+	🟢 Low risk	Indoor corridors, offices, classrooms
Wet	36–50	🟢 Acceptable (HSE benchmark ≥36)	Entrances, kitchens, poolside walkways
Contaminated / Oily	Below 24	🔴 High risk	Industrial workshops, food prep areas

Where floors regularly become wet or greasy, the wet PTV result is the benchmark for compliance. Regular re-testing helps ensure cleaning, maintenance and coatings continue to meet safety thresholds.

R Ratings vs PTV: What’s the Difference?

When assessing slip resistance, you may come across both PTV scores and R ratings. However, they are not interchangeable, and only one is recognised for legal compliance in the UK.

PTV (Pendulum Test Values) are measured using the pendulum device on real floors, under real-world conditions. In contrast, R ratings (e.g. R10, R11) are based on a German ramp test, conducted in a controlled lab.

Here’s how the two compare:

Feature	PTV (Pendulum Test)	R Rating (Ramp Test)
🇬🇧 Recognised in the UK?	✅ Yes	❌ No
Used by HSE?	✅ Yes	❌ No
Test location	✅ On-site	❌ Lab only
Legal admissibility	✅ Yes	⚠️ No

In summary, while R ratings are commonly used in product brochures or by tile retailers, they do not meet UK legal requirements for assessing actual floor safety.

Only PTV values derived from pendulum testing are accepted by the HSE and UK courts.

Pendulum Testing vs Other Slip Resistance Methods

While the pendulum method is the UK’s gold standard, several other tests are sometimes used for product marketing or international comparison. Here’s how they differ:

Test Method	Also Known As	Location	Key Difference	Legal Status in UK
Pendulum Test (BS 7976 / BS EN 16165)	British Pendulum, PTV Test	✅ On-site	Simulates heel strike in wet/dry conditions	HSE Preferred
Ramp Test (DIN 51130)	R Rating Test (e.g. R9–R13)	❌ Lab only	Uses motor oil on an inclined ramp	Not recognised by HSE
SlipAlert / Tribometer	Dynamic CoF Test	✅ Portable	Measures coefficient of friction via slider speed	Accepted for internal QA, not legal proof
Surface Roughness (Ra)	Profilometer Test	✅ On-site	Measures texture only – no slip simulation	Used as supporting evidence

Only the Pendulum Test provides a result (PTV) recognised by the HSE, UKSRG, and UK courts as a true indicator of slip risk.

Where Pendulum Slip Testing Is Required

The HSE recommends Pendulum Testing wherever the floor surface could become wet, worn, polished, contaminated or difficult to manage safely. This can include public buildings, sports stadiums, railway stations, airports, schools, hospitals, commercial kitchens, leisure centres and industrial workplaces.

• Public buildings – schools, hospitals, libraries, and council facilities
• Commercial areas – shops, restaurants, offices, and supermarkets
• Leisure and sports venues – swimming pools, gyms, and stadiums
• Industrial workplaces – factories, warehouses, and vehicle workshops
• Outdoor walkways and ramps – especially where surface water collects

Routine slip resistance testing in these areas helps prove due diligence under the Health and Safety at Work Act 1974 and the Workplace (Health, Safety and Welfare) Regulations 1992.

How to Book a Slip Test

Need to arrange testing? Learn more about our Pendulum Slip Testing services, including what’s covered, how results are reported, and where we operate.

• ✔️ Certified, calibrated equipment
• ✔️ Wet and dry testing
• ✔️ PTV reporting with clear risk ratings
• ✔️ Optional surface roughness measurements
• ✔️ Legally defensible PDF reports

📞 Call: 01254 933 486

📩 Email: info@velocitysafety.co.uk

🌐 Or visit our website to book or request a quote.

FAQs

Here are the most common questions about pendulum slip testing, PTV values, wet testing, legal use and floor safety reports.

What is a Pendulum Slip Test?

A Pendulum Slip Test measures how slippery a floor is using a mechanical tester. It’s the UK’s legally preferred method for assessing real-world slip resistance, particularly in wet conditions.

Is Pendulum Testing a legal requirement?

Not by name – but UK law requires that slip risks be assessed and controlled. Pendulum testing is the most widely accepted method by the HSE, insurers, and courts.

What does PTV mean?

PTV stands for Pendulum Test Value – the number generated by the slip test. A PTV of 36 or higher is considered low slip risk according to HSE standards.

What is a wet pendulum test?

A wet pendulum test measures slip resistance after the surface has been wetted or contaminated to reflect realistic slip conditions. Wet PTV results are often more important than dry results for entrances, kitchens, pool surrounds, changing rooms and outdoor walkways.

What is the British Pendulum Test?

The British Pendulum Test is another name for pendulum slip testing. It uses a calibrated pendulum tester to measure floor slip resistance and produce a PTV score.

How long does a Pendulum Test take?

Testing one surface area takes about 30–60 minutes. Larger sites or multi-zone floors may take longer depending on layout.

Do I need to test wet and dry conditions?

Yes – especially if your floor may become wet. Wet PTV results are often more important for compliance and legal defensibility.

How often should floors be re-tested?

It depends on usage, surface changes, and exposure to contamination. Re-testing is usually advised every 12 months, or after any significant cleaning, wear, or slip incident.

Can I use R Ratings instead of a PTV?

No – R Ratings come from lab-based ramp tests and aren’t accepted in UK legal or compliance frameworks. Only PTV scores from Pendulum Testing meet HSE standards.

Resources & Further Guidance

• HSE: Slips and Trips – Assessing Floor Slip Resistance
• UKSRG Guidelines Issue 6 (PDF)
• BS 7976-2:2019 – Pendulum Method Summary (BSI)
• HSE Legal Framework Overview
• Workplace (Health, Safety and Welfare) Regs 1992 (gov.uk)

“A fire point still needs to be in the right place when the workplace layout changes.”

Fire extinguisher trolleys give businesses a way to position portable firefighting equipment where fixed wall mounting is unsuitable.

They are particularly useful on construction sites, in temporary work areas and across large premises where the fire risks or working zones move. The trolley makes the equipment mobile; the site’s fire risk assessment determines which extinguishers are needed and where the fire point should be located.

This guide explains how to set up a mobile fire point, what to consider outdoors and how to keep it accessible as the site changes.

Explore Velocity Safety’s fire extinguisher trolleys, stands and fire point accessories.

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What Is a Fire Extinguisher Trolley?

A fire extinguisher trolley is a wheeled support for portable extinguishers. Depending on the design, it may hold one or several units and provide space for identification signs or other fire point accessories.

It allows the fire point to be repositioned when a work area changes. The extinguishers still need to be securely supported, correctly selected and readily available in an emergency.

“Mobile fire point” describes the complete arrangement rather than the trolley alone. It includes the equipment, location, identification and arrangements for checking and maintaining it.

Where Are Fire Extinguisher Trolleys Used?

Trolleys are most useful where a permanent bracket cannot reliably serve the area or where the relevant fire risks move during the work.

Typical examples include:

• Construction and demolition sites with changing work zones.
• Temporary cabins, compounds and site entrances.
• Warehouses or production areas with changing layouts.
• Outdoor events and temporary facilities.
• Yards, loading areas and other locations without suitable fixed mounting points.

A wheeled trolley is not necessarily the best choice everywhere. A stable fixed fire point may be better beside a permanent risk, while a freestanding stand or scaffold-mounted fire point may suit a location where the equipment does not need to move.

Are Fire Extinguisher Trolleys a Legal Requirement?

No UK law requires a fire extinguisher trolley by name. The duty is to provide appropriate fire precautions and firefighting equipment for the risks present.

For construction sites, HSE advises placing suitable extinguishers at identified fire points around the site. The Construction (Design and Management) Regulations 2015 require suitable firefighting equipment where necessary and its proper maintenance.

The Regulatory Reform (Fire Safety) Order 2005 requires appropriate fire safety arrangements for relevant premises in England and Wales. The precise legal framework differs elsewhere in the UK.

A trolley can help meet the practical need for an identified, accessible fire point where the layout changes. Whether it is the right arrangement depends on the fire risk assessment.

What Should a Mobile Fire Point Include?

The fire risk assessment should determine the equipment. A practical setup may include:

• Suitable extinguishers: Selected for the materials, equipment and processes in the area. There is no universal combination for every trolley.
• Secure supports: Brackets or retainers suited to the number, size and weight of the extinguishers.
• Clear identification: Location and extinguisher signs appropriate to the site and its signage arrangements.
• Weather or impact protection: Cabinets or covers where exposure could damage equipment or affect its readiness.
• Additional equipment where the assessment calls for it: For example, a fire blanket or a local means of raising the alarm.

The trolley should not be treated as a substitute for the site’s overall alarm and evacuation arrangements. People need to know how to raise the alarm, leave safely and contact the fire and rescue service.

See Velocity Safety’s extinguisher supply and installation service for help selecting the right units.

How Should a Fire Extinguisher Trolley Be Positioned?

A mobile fire point should be easy to find and reach when needed. Before placing it, check:

1. The risk: Is the point located to serve the work area and the fires identified in the assessment?
2. Access: Can people reach the extinguishers without climbing over stored materials or moving equipment?
3. Escape: Does the trolley leave exits and escape routes clear?
4. Stability: Is it secure on the ground surface and protected from unintended movement or vehicle impact?
5. Visibility: Can workers identify the fire point, including when temporary structures or stored materials change the view?
6. Ongoing checks: Who will confirm that the equipment remains present, accessible and in the agreed location?

If the work zone moves, review where the trolley is needed next. Update site plans or briefings where its position forms part of the fire safety arrangements.

Can Fire Extinguisher Trolleys Be Kept Outdoors?

They can be used outdoors if the trolley and extinguishers are suitable for the environment and remain protected and accessible.

Consider rain, corrosion, dust, frost, direct sunlight, ground conditions, accidental impact and tampering. Depending on the equipment and exposure, a suitable cabinet or cover may be needed. Check the operating temperature marked on each extinguisher; some extinguishing media can be affected by freezing conditions.

Our fire extinguisher temperature and outdoor storage guide explains these risks in more detail.

Fire Trolley, Freestanding Stand or Wall Bracket?

Choose the mounting arrangement according to how the area is used.

Velocity Safety supplies trolleys, stands, cabinets and scaffold fire point stands for different site arrangements.

How Should Mobile Fire Points Be Checked and Maintained?

A changing site can leave a trolley blocked, moved without notice or exposed to damage. Include it in routine site checks:

• Confirm the trolley is still in its agreed position and is stable.
• Check that each extinguisher is present, accessible and secured.
• Look for discharge, damage, corrosion, missing pins or seals, and pressure readings outside the acceptable range where a gauge is fitted.
• Check that signs remain visible and any cabinet or cover can be opened quickly.
• Record defects and arrange prompt corrective action.

Portable extinguishers also need servicing in line with the applicable maintenance programme and BS 5306-3 servicing guidance. Moving them onto a trolley does not change their maintenance needs.

Final Takeaway

A fire extinguisher trolley is a practical way to provide a movable fire point. Its value lies in keeping suitable equipment together and accessible as a work area changes.

Start with the fire risk assessment, select the right extinguishers and location, then check that the trolley remains stable, identifiable, protected and properly maintained.

Frequently Asked Questions

What is a fire extinguisher trolley?

It is a wheeled support for one or more portable fire extinguishers. It can form part of a mobile fire point where equipment needs to move with the work area.

Are fire extinguisher trolleys legally required?

No. The legal duty concerns suitable fire precautions and equipment for the risks present. A trolley is one practical way to position extinguishers where fixed mounting is unsuitable.

Does every construction site need a mobile fire point?

Construction sites need suitable fire safety arrangements based on their risks. HSE advises identified fire points with appropriate extinguishers. The number, equipment and mounting method depend on the site.

Which extinguishers should go on a trolley?

That depends on the potential fires in the area. Select extinguishers through the fire risk assessment rather than loading every trolley with the same combination.

Can a trolley be left outdoors?

Yes, where the equipment is suitable and protected against the conditions. Consider weather, operating temperature, corrosion, impact and tampering when specifying the trolley and any covers or cabinets.

Can I move the fire point whenever I need to?

It can be repositioned, but the new location must still provide suitable coverage and remain accessible and identifiable. Communicate and record changes where the fire point’s location forms part of the site fire plan.

Do trolley-mounted extinguishers need servicing?

Yes. They still require routine user checks and servicing in accordance with the applicable maintenance arrangements. The trolley and its supports should also be checked for damage and stability.

Does Velocity Safety offer trolley hire?

Velocity Safety’s published service covers trolley supply and installation. Contact the team to discuss the arrangements available for a temporary project.

Resources

• • HSE – General Fire Safety on Construction Sites
  • HSE – Fire Safety in Construction, HSG168
  • GOV.UK – Workplace Fire Safety Equipment and Maintenance
  • BSI – BS 5306-8: Selection and Positioning of Portable Fire Extinguishers

 

Gas detector calibration protects lives – and keeps you legally compliant.

Gas detection units (GDUs) are essential for identifying hazardous atmospheres – but their accuracy degrades over time. If not properly calibrated, detectors can give false readings or fail to trigger alarms at dangerous gas levels. In this guide, we’ll explain what GDU calibration is, how often it’s required, and what UK law expects from responsible employers.

Regular gas detection unit (GDU) calibration ensures your detectors respond accurately to gas hazards and supports your legal responsibilities under UK health and safety law.

Here’s what this guide covers:

What Is a Gas Detection Unit (GDU)?

A GDU is a fixed or portable device designed to detect harmful levels of gas – including flammable, toxic, and oxygen-deficient atmospheres.

Use cases include:

• Confined spaces (e.g. tanks, voids, basements)
• Manufacturing and industrial plants
• Laboratories and cleanrooms
• Waste, utilities, and energy sites
• Engine test cells and plant rooms

Accuracy is critical. Even a functioning detector may give false confidence if not properly calibrated.

What Does GDU Stand For?

GDU stands for Gas Detection Unit. The term is commonly used to describe fixed gas detectors and gas monitoring devices used to identify hazardous atmospheres before they become dangerous to people, property or operations.

Depending on the application, a GDU may monitor oxygen depletion, flammable gases, toxic gases or refrigerant leaks. These systems are commonly installed in plant rooms, manufacturing facilities, laboratories, utilities infrastructure and confined spaces.

Why GDU Calibration Matters

Gas sensors degrade over time due to:

• Environmental exposure (dust, temperature, humidity)
• Mechanical impact or vibration
• Sensor ageing and contamination (e.g. silicone vapours)

How Often Should GDUs Be Calibrated?

Calibration frequency depends on:

• Sensor type (e.g. catalytic bead, electrochemical, IR)
• Manufacturer guidance
• Environmental conditions
• Frequency and type of use

Calibration Frequency	Recommended For
Every 6 months	Most fixed systems (HSE-aligned standard)
Every 3 months	Harsh or high-risk environments
Before each use	Portable detectors used in confined spaces
After impact/failure	Any GDU showing drift, error, or exposure

✅ If unsure, 6-monthly calibration offers a reliable, defensible minimum for most systems.

What Does GDU Calibration Involve?

Calibration is a formal process where sensors are tested and adjusted using certified calibration gas.

Steps include:

• Applying traceable calibration gas to the sensor
• Zeroing the detector in fresh air
• Checking alarm setpoints and response time
• Adjusting sensor output if necessary
• Issuing a calibration certificate (with expiry and engineer ID)

📋 Velocity Safety uses test gases traceable to national standards and works to manufacturer specs to ensure legal defensibility.

Bump Testing vs Calibration

These are not the same – and only one meets compliance expectations:

Test Type	Purpose	When to Use
Bump Test	Quick check: confirms sensor response to gas	Before each use (especially portables)
Calibration	Full accuracy adjustment & verification	Every 3 – 6 months, or after impact/fault

❗ A bump test only checks if the sensor reacts – not whether the reading is accurate. It does not replace calibration.

Legal & Safety Requirements

Employers are legally required to maintain and verify the function of gas detection systems under several UK regulations:

• Health and Safety at Work etc. Act 1974 (Sections 2 & 3)
• DSEAR 2002 – Dangerous Substances and Explosive Atmospheres Regulations
• COSHH 2002 – Control of Substances Hazardous to Health
• PUWER 1998 – Provision and Use of Work Equipment Regulations

While these laws don’t specify fixed calibration intervals, failing to calibrate may be seen as a breach of your duty of care – especially if a gas-related incident occurs.

You are expected to:

• Maintain gas detection systems in a safe condition
• Ensure accuracy through regular calibration
• Retain traceable calibration records
• Act quickly on faults, failures, or alarms

Who Is Responsible for Gas Detector Calibration?

Under UK health and safety law – particularly the Health and Safety at Work Act 1974 – the responsibility for GDU calibration falls to the:

• Employer
• Duty holder
• Or person in control of premises or safety systems

In practice, this means:

• Scheduling and documenting calibration
• Following manufacturer guidance or risk-based plans
• Acting on faults or failed accuracy checks

In the event of an incident, the enforcing authority (HSE or local authority) will expect to see evidence that reasonably practicable steps were taken to manage risk – including GDU maintenance.

How Long Do Sensors & GDUs Last?

Typical gas sensor lifespan: 2 – 5 years, depending on:

• Sensor type
• Exposure conditions
• Maintenance and handling

⚠️ Accelerated degradation can occur due to:

• High gas concentrations
• Harsh environments (heat, dust, vibration)
• Contaminants (solvents, vapours, silicone)

Warning signs of sensor failure:

• Slower response time
• Inconsistent zeroing
• Frequent false alarms
• Failed bump tests

Velocity Safety can assess your equipment and advise whether recalibration or sensor replacement is available.

Common Gases Detected & Industries That Use GDUs

GDUs are essential wherever gas or vapour risks are present. Common gases and vapours include:

Common gases and vapours:

• CO (Carbon Monoxide)
• CO₂ (Carbon Dioxide)
• O₂ (Oxygen depletion)
• H₂S (Hydrogen Sulphide)
• CH₄ (Methane)
• VOCs (Volatile Organic Compounds)
• NH₃ (Ammonia)
• NO₂ (Nitrogen Dioxide)

Industries supported:

• Construction & Demolition (confined space entry)
• Utilities & Energy
• Manufacturing & Chemical Processing
• Fuel Storage & Distribution
• Logistics Hubs & Cold Stores
• Laboratories, Cleanrooms & Hospitals

Need Professional GDU Calibration Support?

FAQs

How often should gas detectors be calibrated?

Most fixed GDUs should be calibrated every 6 months. In harsher or higher-risk environments, quarterly calibration may be required to stay compliant and ensure accuracy.

Is gas detector calibration a legal requirement in the UK?

Yes. While the law doesn’t specify exact intervals, regulations like COSHH, DSEAR, and the Health and Safety at Work Act require employers to maintain safe equipment. Regular calibration is the recognised method to prove compliance.

Do portable gas detectors need calibration?

Absolutely. Portable detectors should be bump tested before each use and fully calibrated every 3 – 6 months, depending on use, environment, and manufacturer guidance.

What happens if a GDU fails a bump test?

It must be removed from use immediately. A failed bump test suggests the sensor is no longer reliable – it may need recalibration, servicing, or full replacement depending on the fault.

Does a bump test confirm accuracy?

No. A bump test only checks whether the sensor responds to gas – not if the reading is correct. Only a full calibration can confirm sensor accuracy.

What’s included in a gas detector calibration?

Calibration involves applying a known gas concentration to the sensor, adjusting output if needed, checking alarm thresholds, and issuing a certificate for audit purposes. It ensures both safety and regulatory compliance.

Who is responsible for calibrating GDUs?

The employer, duty holder, or site manager is typically responsible. They must ensure calibration is carried out at suitable intervals and maintain traceable records for inspections or investigations.

What are the calibration requirements for gas detectors?

Gas detectors should be calibrated at intervals based on manufacturer guidance, risk assessment, sensor type and environmental conditions. Employers must be able to demonstrate that gas detection equipment remains accurate, maintained and suitable for the hazards being monitored.

Can I calibrate gas detectors in-house?

In some cases, yes – if you have the right test gas, equipment, training, and manufacturer procedures. However, many businesses choose professional calibration to guarantee accuracy and meet HSE audit expectations.

Resources & Further Guidance

• HSE INDG370 – Brief Guide to DSEAR
• HSE L137 – DSEAR ACOP & Guidance
• PUWER 1998 Overview
• HSE – Maintaining Work Equipment
• COSHH Guidance

“The risk depends on both how strongly a tool vibrates and how long it is actually used.”

A hand-arm vibration (HAV) risk assessment identifies which workers are exposed to vibration, estimates their daily exposure and sets out how the risk will be controlled.

For some workplaces, suitable vibration data and a realistic estimate of tool use are enough to make those decisions. Where the available figures do not represent how tools are used on site, professional measurement can provide more reliable evidence.

This guide explains the assessment process, the 100-point and 400-point thresholds, when tool testing helps, and when workers need health surveillance.

Explore Velocity Safety’s hand-arm vibration measurement and assessment service.

Jump to:

What Is Hand-Arm Vibration?

Hand-arm vibration is vibration transmitted into the hands and arms while using hand-held or hand-guided equipment. It can also pass through a workpiece held against a powered machine.

Examples include breakers, hammer drills, grinders, impact tools, chainsaws, strimmers and vibrating manufacturing processes.

Regular exposure can contribute to hand-arm vibration syndrome (HAVS) and carpal tunnel syndrome. Possible symptoms include tingling, numbness, loss of dexterity and fingers turning white in the cold. Employers should encourage workers to report symptoms promptly so the risks and their exposure can be reviewed.

How Do You Carry Out a HAV Risk Assessment?

The Control of Vibration at Work Regulations 2005 require employers to assess and control vibration risks. A useful assessment follows the actual work rather than relying only on a list of tool specifications.

1. Identify the tools and processes. Record the equipment, accessories, materials and tasks that transmit vibration to workers’ hands.
2. Identify who uses them. Include workers who switch between tools or tasks during the same day.
3. Establish representative vibration magnitudes. Use suitable HSE, supplier or workplace data. Consider measurement where available figures do not represent the work.
4. Establish actual trigger times. Observe how long each worker’s hands are exposed while the tool is operating. Time spent holding an idle tool does not count as trigger time.
5. Estimate daily exposure. Use the HSE calculator or exposure points system to combine the tools and tasks used by each worker.
6. Decide and record what action is needed. Identify controls, workers requiring health surveillance, responsibilities and a timetable for improvements.

The assessment should be based on a reasonable estimate. If workers use several vibrating tools, overlooking one task can understate their total exposure.

How Do HAV Exposure Points Work?

Exposure points express a worker’s daily hand-arm vibration exposure in a way that makes different tools and trigger times easier to combine.

A tool’s vibration magnitude is expressed in metres per second squared (m/s²). Daily exposure is expressed as A(8), an eight-hour equivalent value. Points give another way to present that daily result:

• 100 points per day: the Exposure Action Value.
• 400 points per day: the Exposure Limit Value.

For example, using a tool with a representative vibration magnitude of 5 m/s² for two hours of actual trigger time produces approximately 100 points. If the worker then uses another vibrating tool, its points must be added to the same daily total.

The HSE hand-arm vibration exposure calculator accepts vibration magnitude and exposure duration for multiple tools and calculates both A(8) and exposure points.

What Is the Difference Between the EAV and ELV?

Both values apply to an individual worker’s total daily hand-arm vibration exposure.

Exposure below the EAV does not mean a tool presents no risk under every circumstance. The assessment must still consider how often exposure occurs, the workers involved and any reported symptoms.

When Is On-Site HAV Measurement Needed?

A HAV risk assessment does not automatically require every tool to undergo a measured test. HSE advises that vibration magnitudes need to be measured when suitable data for the assessment cannot be obtained from other sources.

Manufacturer figures are useful for comparing products, but a declared value may not represent the vibration experienced during a particular workplace task. The accessory, material, tool condition, work method and operator can all affect the result.

On-site measurement can be particularly useful when:

• Available data is missing, inconsistent or unlikely to reflect actual tool use.
• Different accessories or materials may change vibration substantially.
• The estimated exposure sits close to an action or limit value.
• The employer needs better evidence to compare tools or assess whether controls work.
• Workers report symptoms or unexpectedly high vibration.

Velocity Safety measures tools and processes in use to support workplace HAV assessments.

What happens during professional HAV measurement?

A competent assessor gathers details of the tool, task and operating conditions, then uses suitable calibrated vibration measurement equipment while representative work is carried out.

The vibration transducer is mounted appropriately near where vibration enters the hand. The resulting vibration magnitude is considered alongside realistic trigger-time information to estimate exposure for the workers and tasks involved.

A useful report should identify what was measured, the operating conditions, the results and the assumptions used in any exposure calculations. The employer can then use the findings to update its assessment and control plan.

HAV Tool Timers vs Vibration Measurement: What Is the Difference?

A tool timer, logbook or electronic monitoring system can help estimate how long equipment is used. Professional vibration measurement establishes a representative vibration magnitude for a tool and task.

Some monitoring systems combine recorded time with an entered vibration value to estimate points. Their result depends on whether that value represents the actual work. A wrist-worn timer should not be treated as a direct measurement of vibration transmitted into the worker’s hand.

HSE also cautions that continuous monitoring alone does not control the risk. Employers still need suitable work methods, equipment and exposure controls.

How Can Employers Reduce HAV Exposure?

The assessment should lead to practical changes. Depending on the task, these may include:

• Changing the method: Mechanise a task or use a process that removes the need for a hand-held vibrating tool.
• Choosing suitable equipment: Select a lower-vibration tool that can complete the job efficiently. A tool that takes much longer can increase total exposure.
• Maintaining equipment and accessories: Replace worn bits, blunt chisels and damaged grinding consumables; follow the manufacturer’s maintenance instructions.
• Planning the work: Reduce unnecessary trigger time and distribute tasks so one worker does not receive excessive daily exposure.
• Training workers: Explain tool selection, correct use, symptoms and how to report problems.

Gloves may help keep hands warm, but they should not be relied upon as the main means of reducing vibration exposure.

When Is HAVS Health Surveillance Required?

HAVS health surveillance checks workers for early signs of vibration-related ill health. It is separate from measuring a tool or calculating daily exposure.

HSE says employers must provide health surveillance for workers who, despite controls, are likely to be regularly exposed above the EAV, or who are considered at risk for another reason.

An appropriate programme may start with regular symptom questionnaires and refer positive responses for occupational health assessment. Employers should act on advice about continued exposure and use the findings to review their risk assessment and controls.

A tool measurement report can help identify who may need surveillance. It does not replace the surveillance itself.

How Often Should a HAV Risk Assessment Be Reviewed?

Review the assessment when changes could affect exposure, including:

• New tools, accessories, materials or work methods.
• Changes in how often or how long workers use equipment.
• Equipment wear, poor maintenance or unexpected vibration.
• Reported symptoms or findings from health surveillance.
• Evidence that existing controls are not working.

Review it regularly even when work appears stable. HSE advises that employers should not leave it for more than about two years without checking whether a review is needed.

There is no universal rule requiring every tool to be professionally measured once a year. Repeat measurement when it is needed to keep the exposure estimate representative or to verify a change in controls.

Final Takeaway

An effective HAV risk assessment connects the work people actually do with representative vibration data and realistic trigger times. It adds exposure from different tools across the day, identifies who is approaching the EAV or ELV and leads to controls that reduce the risk.

Where existing vibration figures cannot support a reliable assessment, on-site measurement helps replace assumptions with evidence.

Frequently Asked Questions

Is a hand-arm vibration risk assessment a legal requirement?

Employers must assess the risk to workers exposed to vibration under the Control of Vibration at Work Regulations 2005. The findings should identify exposure, necessary controls and any workers who need health surveillance.

Does every vibrating tool have to be measured?

No. An assessment can use suitable representative data from HSE, suppliers or other reliable sources. Professional measurement is needed when suitable vibration data cannot be obtained another way.

What is trigger time?

Trigger time is the time a worker’s hands are exposed to vibration while the equipment is operating. It can be much shorter than the total time spent on a job or holding the tool.

What do 100 HAV exposure points mean?

One hundred points is equivalent to the daily Exposure Action Value of 2.5 m/s² A(8). Reaching this level triggers a planned programme of measures to reduce vibration exposure.

What do 400 HAV exposure points mean?

Four hundred points is equivalent to the daily Exposure Limit Value of 5.0 m/s² A(8). It is a limit that must not be exceeded, rather than a target for normal working.

How do you account for several tools used in one day?

Estimate the exposure contribution of each tool or task from its representative vibration magnitude and trigger time. Add the exposure points to establish that worker’s daily total.

Can a HAV timer measure tool vibration?

A timer records or estimates use duration. It does not, by itself, measure the vibration magnitude transmitted into the hands. Any exposure calculation using timer data also needs a suitable vibration value.

When is HAVS health surveillance needed?

Provide it where workers are regularly likely to be exposed above the EAV despite controls, or are otherwise considered at risk. It checks for signs of ill health and is separate from tool testing.

How often should HAV testing be repeated?

There is no universal annual tool-testing interval. Review the assessment when work or exposure changes and regularly thereafter; repeat professional measurement when the existing data is no longer representative or better evidence is needed.

Resources

• • HSE – Vibration Risk Assessment
  • HSE – Control of Vibration at Work Regulations 2005
  • HSE – Hand-Arm Vibration Exposure Calculator
  • HSE – Measurement and Monitoring Guidance
  • HSE – Protecting Workers and Providing Health Surveillance