A technical comparison of BS EN 16034 and BS 8524

An Adexon® white paper
Read time: 36 minutes

Table of Contents

1. Introduction

Fire curtains are a critical fire safety product which, when used correctly and in adherence with current regulations, offer designers a multitude of new architectural possibilities whilst maintaining excellent fire compartmentation and protection of escape routes.

This white paper is aimed at fire engineering consultants, architects and purchasers. It looks at product standards used in the UK for vertical fire curtains (hereinafter referred to as fire curtains).

We provide a detailed technical comparison of the two most prevalent fire curtain standards used in the UK, BS EN 16034 and BS 8524. The former is legally required, and the latter is marketed as required. It is important to know, as BSi tell us, that “standards aren’t the same as regulations and following a standard doesn’t guarantee that you’re within the relevant laws. In fact, standards rarely cite the law as legislation could change within the lifetime of the standard”1.

The primary importance is compliance with the regulations. If you would like a deep dive into these, our white paper ‘Fire curtain regulations in the UK’2 will help.

We will discuss ISO 21524, “Fire resistance tests — Elements of building construction — Requirements for active fire curtains” in another article. ISO 21524 is the only product standard used in the UK with third-party certification from a Notified Body that specifically covers horizontal fire curtains.

The unique and intricate design of horizontal fire curtains reinforces only using ISO 21524 third-party certified products for them (horizontal fire curtains).

ISO 21524 is an excellent product standard but, unfortunately, as with BS 8524-1, it is not a harmonised standard and hence cannot offer legal compliance to the Construction Products Regulations for vertical fire curtains, hence limiting its use.

When we refer to third-party certification, we are referring to third-party certification to product standards such as BS EN 16034, BS 8524-1, and ISO 21524, NOT just third-party certification to an individual product test. We always advocate using third-party certification to a product standard where available, as opposed to third-party certification to just a product test such as the fire resistance test BS EN 1634-1:2014. Third-party certification to product standards progressed life safety considerably over 10 years ago, and we do not advocate going backwards where a product standard is available.

A product standard is a combination of complimenting product tests. For example, BS 8524-1 and BS EN 16034 are both product standardswith an extensive list of product tests e.g., they both have the same:

  • fire test (BS EN 1634-1:2014)
  • smoke test (BS EN 1634-3:2004)
  • cycle test

Note, for ease we mostly refer to BS 8524 Part 1 simply as ‘BS 8524’ in this white paper.

For context, in the BSi publication of BS EN 16034, the foreword of the harmonised standard states, “This European Standard shall be given the status of a national standard… and conflicting national standards shall be withdrawn at the latest by October 2019.” As can be seen from the scope of BS EN 16034 (see more in section 7 of our white paper, ‘Fire curtain regulations in the UK’2) it is clear that BS 8524 is a national standard that conflicts with BS EN 16034. Both cover fire curtains and it is semantics to seek to differentiate between operable fabric curtains and active fire curtain barrier assemblies (or active fire curtains of some other description). If you order a fire curtain that is tested to BS EN 16034 and you order one that is tested to BS 8524, you will get two of the same product. There may be scope for a future version of BS 8524 for concertina fire curtains and horizonal fire curtains (but not vertical fire curtains). This is because as BS EN 16034 does not cover concertina and horizontal configurations of fire curtains so there would be no conflict. You will see more by reading on.

BSi have added a ‘National foreword’ that refers to BS 8524, “This standard [BS EN 16034] does not cover their operation deployment speeds, initiation devices or warning devices, etc. and as such should comply with BS 8524-1 and BS 8524-2″. We go over this in detail in our white paper, ‘Fire curtain regulations in the UK’2.

They go on to say in bold, ‘Compliance with a British Standard cannot confer immunity from legal obligations‘. ‘Legal obligations’ includes compliance with the CPR for construction products as evidenced by a CE mark from a Notified Body. We also go over this in our white paper ‘Fire curtain regulations in the UK’2.

2. Common Standards

BS 8524 is a national standard that conflicts with BS EN 16034 as referred to in the harmonised standard foreword of BS EN 16034. You will see more about why these two are conflicting standards by reading on. In reading this white paper you will see where the standards cross-over technically, and where they have differences. However, the technical and content differences are not to be confused with the application of both covering the same product, vertical fire curtains.

What is BS EN 16034:2014?

In short, the scope of 16034 is to identify safety and performance requirements applicable to all products intended to be used in fire and/or smoke compartmentation or protecting escape routes, specifically doorsets, rolling shutters, openable windows and operable fabric curtains. The performance specifications include references to other standards which contain definitions for fire resistance and smoke control. BS EN 16034 is the only harmonised standard to cover vertical fire curtains.

What is BS 8524-1:2013?

Part 1 of BS 8524 specifies requirements for the design, testing and classification of active fire curtain barrier assemblies. It includes performance aspects relating to the reliability, durability, fire resistance, smoke containment and impact resistance of active fire curtain barrier assemblies, their control devices and ancillary equipment. BS 8524-2 is a code of practice related to installation and maintenance but it is dependent on the product being available.

We cover BS 8524-2 in more detail in our white paper, ‘Safety is the standard – a detailed look at British Standard BS 8524 and why it can no longer be used for fire curtains.’10

Both standards are fairly comprehensive and technical, as would be expected in documents used to determine the performance criteria of a life safety critical product. In the following sections we examine the technical overlaps, and the technical differences between these two product standards for fire curtains.

3. Technical Similarities

Both include the same fire test

Both BS 8524-1:2013 and BS EN 16034:2014 use the same fire test standard (BS EN 1634-1:2014+A1:2018) to ascertain the fire performance of the system (although BS 8524 also allows the option to use BS 476 – see more below). The fire curtains are installed in a furnace and are subject to high temperatures (to replicate a fire scenario), following a standard heat curve to ensure test conditions are consistent (Fig 1). The standard EN 1363-1:2020 stipulates the equipment and procedures for conducting the fire test.

Once completed, the product is classified on the basis of integrity (E), radiation and integrity (EW), or insulation and integrity (EI), in accordance with the classifications in BS EN 13501-2:2007+A1:2009.

Both include the same smoke test

Both standards use the same test to ascertain smoke control, BS EN 1634-3, which determines the leakage of smoke from one side of the fire curtain to the other. Smoke leakage is measured in m3/lm/hr where the ‘lm’ is the number of linear metres around the perimeter of the product (excluding the threshold).

Both include the same cycle test

Both standards request a usage cycle test to determine the safe number of operations a system can perform during its working life. The classification is identical between the standards and is graded on a scale from class 0 (up to 499 cycles) to class 5 (200,000 cycles or more).

One of the benefits cited in BS 8524 is that the cycle test is carried out before the fire test. In theory this could seem beneficial but in real life, where do the issues with fabrics arise? 98% are at the retention points and this frequent failing is not tested in a fire rendering this ordering of tests of little value. The results of this are seen in some of the poorest and least reliable fire curtains on the market having passed BS 8524 with this requirement.

Both standards are considered suitable for fire curtains protecting escape routes

Efectis have certified fire curtains with “Intended use: Fire/smoke compartmentation and on escape routes” to “Harmonised standards: BS EN 16034: 2014 BS EN 13241: 2003+A2: 2016” evidencing fire curtains complying with EN 16034 are safe for use on escape routes. Efectis are an audited UKAS accredited (or equivalent) Notified Body and an authority on compliance.

Historically, BS 8524 has also been accepted as addressing the issue of escape routes. Some in the industry question the equivalence of the two standards in this regard. For example, the ASFP Black Book says “the standard [BS EN 16034:2014] omits the safety features regarded by BS 8524 as critical to secure a safe protected escape… fire and smoke resistance for the purpose of means of escape is not referred to… Consequently, ASFP is of the opinion that operable fabric curtains [referring to 16034] are not suitable for protected escape routes”3.

However, there is nothing further said as to which safety features are critical for escape routes. If it is the issue of ‘tenable area’, there is further discussion of the proximity of personnel to a fire curtain during a fire in the ‘Hot motor test’ section of this white paper (see below).

Both standards are applicable to all applications of vertical fire curtains where a person could be underneath.

BS EN 16034 refers to retail premises in its scope. You may ask, What about fire curtains outside this application?

We had this excellent question from the audience at our talk in the Innovation & Regulation Theatre at the Fire Safety Event on 27th April 2023. The talk was titled, “Fire curtain compliance in the UK: The status quo of BS 8524 and BS EN 16034” last week.

It is a good point to raise and one that requires further reading of the standard. If you read the scope of BS EN 16034 you will notice it says “requirements applicable to all fire resisting and/or smoke control products intended to be used in fire and/or smoke compartmentation and/or escape routes, which are EITHER:

  • industrial, commercial… etc…. OR
  • rolling shutters… etc… OR
  • pedestrian doorsets… etc…” and so on.

Without re-typing out the whole standard here (we always recommend checking the original text yourself) it goes on to give definitions in section 3:

  • A “doorset” is defined as a whole range of items including “rolling shutter and/ or operable fabric curtains including any frame or guide” or “rolling or folding curtain”.
  • An “operable fabric curtain” is defined as a “doorset with leaf constructed from woven material… which functions as a rolling shutter”

It can be seen the author is seeking to include as wide a description as possible so as to provide cover for doors with similar characteristics. What is quite plain is that a ‘doorset’ includes fire curtains, and a pedestrian doorset includes fire curtains that can be passed under by a pedestrian (in simple speak). Language (English or any other) is plain in the use of ‘either’, ‘or’, and commas; a single term is relevant in isolation without being dependant on any other term, much like contracts will invariably say ‘should one clause be unenforceable it shall not render any other clauses unenforceable’.

Accordingly, it is accurate to say the definition for a ‘doorset’ in BS EN 16034 is a “rolling shutter and/ or operable fabric curtain including any frame or guide” or “rolling or folding curtain”. It is true to read this singularly like this.

Obviously a ‘doorset’ includes many other products too.

As such, BS EN 16034 covers vertical fire curtains where a person could potentially be under it, and therefore vertical fire curtains must be CE marked to it (BS EN 16034) since 1st November 2019.

4. Technical Differences

BS 476

BS 8524-1 has 30 references to BS 476, whilst BS EN 16034 has none. Examples in BS 8524-1 include:

  • “5.5.2.1 The barrier assembly shall… complete a test for smoke leakage at ambient temperature in accordance with BS 476-31.1 or BS EN 1634-3:2004”;and
  • “5.6.1.1 The fire resistance of the barrier assembly shall be determined in accordance with the standards specified in Table 3…

BS 476 is an example of a British Standard that is inferior to its European Standards counterpart. We have clung onto it in the UK for over 20 years to suit the manufacturers. This is an example of ‘commercial interests’ being put ahead of fire safety. Commercial interests were referred to by Richard Millet, KC, Lead Counsel to the Grenfell Tower Inquiry, in his closing statements in November 2022 as a contributory factor:

“Behind all of these discrete factors there lay complex, opaque, and piecemeal legislation and an overreliance by law and policy makers on guidance, some of which, including the statutory guidance, was ambiguous, dangerously out of date, and much of which was created by non-governmental bodies and influenced by commercial interests” [emphasis added]

Even now, after the Building Safety Act has finally proposed to remove BS 476, there is still a call in the UK for a transition period to be longer than 12 months so manufacturers can keep on selling potentially inferior and untested products for longer. This is not something we see as good for fire safety.

Under the Building Safety Act, we are seeing the removal of British Standards and Classes in favour of the European Standards. Some points as to why this should be welcomed are:

  • BS 476 withdrawal has been the direction of travel for a number of years.
  • Grenfell tightening-up of standards and competency has resulted in this.
  • European Standards generally have technically better and more thorough test methods
  • European Standards classification system (REI and W), and the EXAPs (Extended Applications):
      • Are a very rigid, rules-based system, using calculation methods, and expert judgements already agreed and written down in a CEN Standard.
      • Are more reliable and conservative than the BS system of ‘likelihood’ assessments allowed under the code of practice, the Passive Fire Protection Form (PFPF)
      • Replace the ‘likelihood it will be ok’ site assessments previously allowed under the BS system, and this will lead to better planning and client value.
      • Only allow installation of what is tested or has a third party approved EXAP. This is long overdue; certified security products have had be installed exactly as tested and certified for over 15 years. If you want to swap a hinge or a closer or a vision panel, you have to have it tested. How much more should fire products have to be tested in every combination required on site rather than having ‘should be ok’ assessments.
  • Products undergoing a European fire test have 10-30% higher thermal exposure (use of plate thermometer) than the British Standards counterpart. This means improved product safety. For example, a 60-minute fire curtain under BS 476 may only achieve 50 minutes (E50) in the European test.

BS 8524 allows ‘should be ok in the event of a fire’ assessments.

This may be pushed back on as being too blunt an appraisal of the Passive Fire Protection Forums (PFPF) code of practice used under BS 476. Whilst BS 8524-1 includes the European Tests they are only optional, not mandated. As well as the numerous references to BS 476 in BS 8524-1, and what is allowed under those tests, here are some other extracts from BS 8524-1 around these ‘evaluations’ [emphasis added]:

  • “5.6.1.2 Where the largest barrier assembly in the range is larger than the size of the specimen tested, a formal engineering evaluation shall be carried out for fire resistance.”
  • “5.6.1.3 Where manufacturers’ installation instructions include installation into other supporting constructions than that tested, a formal engineering evaluation shall be carried out for fire resistance.”
  • “6.2 Integrity. The barrier assembly shall be evaluated against the integrity performance criteria specified in the relevant test method (see Table 3)”
  • “5.6.3 Insulation. Where an insulation classification is required… the barrier assembly shall be evaluated against the insulation performance criteria specified in the relevant test method (see Table 3).”

BS EN 16034 does not allow any of these ‘likelihood’ or ‘should be ok’ appraisals and evaluations for performance. As a European Standard, it generally has technically better and more thorough test methods.

As we saw above, European Standards classification system (REI and W), and the EXAPs (Extended Applications) are a very rigid, rules-based system, using calculation methods, and expert judgements already agreed and written down in a CEN Standard.

Hot motor test

BS 8524-1 requires fire curtains to conduct a hot motor test, where the motor must operate 12 times over 30 minutes with the furnace temperature at 400°C ± 20°C.

In theory this could be seen as a good test, as it potentially shows the robustness of the curtain’s control mechanism, even under extreme conditions. However, our view is that a fire curtain should never be operable if the temperature in the immediate vicinity of the fire curtain is 400°C . The reason for this is that these temperatures would pose a severe-to-fatal risk to the operator and could allow the fire to pass beyond the designated compartmentation barrier and thus endanger the whole building.

Hot water burns us at around 70°C. It scalds us at 100°C. The emergency services would not open a fire curtain with the temperature at even half of the 400°C as it would exceed the limits to which firefighters are trained; see “Characterizing a Firefighter’s Immediate Thermal Environment in Live-Fire Training Scenarios” which states “severe training conditions generally [exposed firefighters to] temperatures between 150°C and 200°C”4

It could be argued that the hot motor test is for applications where the motor is high above the operator, for example in a ceiling void, and it is still safe to operate the curtain lower down. In this situation, if there were a fire or hot smoke and gases high up in the ceiling void and not lower down, and if you wanted to operate the fire curtain, you have a rare combination where a hot motor use may be applicable. A lot of ‘ifs’.

However, as well as the incidence rate of this combination being very rare, who is going to stop the curtain opening above the safe temperature limit so as to prevent the fire spreading? If it is 400°C up where the motor is, and 20°C down where the operator is, what is the temperature in-between? 1m above the operator it could be 250°C, at 1.5m up it could be 300°C, and so on. What height and temperature is it safe to open the fire curtain to in this situation?

Who is going to know this, and how are they going to control it? And will they do this when escaping from a fire? The answers respectively are ‘unknown’, ‘no one’, ‘no method available’, and ‘highly unlikely’. The hot motor test is a hypothetical benefit with a real-life safety score of zero.

The fire curtain will open fully once the Emergency Retract Button is pressed and there is no current method of stopping the curtain on its ‘up’ travel until it reaches the headbox.

To justify this test being of potential value, data is required to show how often the combinations occur where the capability to open a fire curtain when the motor is at 400°C would be a potential benefitand control measures are required including easy-to-use instructions by the user in a fire situation, so they cannot open the fire curtain when unsafe, or open it too far and thus endanger the whole building. A failsafe back-up to stop the fire spreading is also required in the event of user-error.

However, perhaps the biggest flaw in the hot motor test is that it does not reflect real life operation.

In the hot motor test there is no test of the Control Panel. The motor relies on the Control Panel to operate. Without the Control Panel the motor will not operate.

In real life the Control Panel is typically installed at high level with the motor. It is unlikely that much will be left of the Control Panel (plastic contacts, printed circuit board, and other plastics) at temperatures over 100°C, let alone higher.

In conclusion, the hot motor test is an unsafe capability to have without significant control measures being introduced. These control measures are likely impractical to introduce and ensure in real life.

The hot motor test is also misleading. It implies the fire curtain will be operable up to temperatures of 400°C. This is, at best, unknown and, being realistic, highly unlikely. The Control Panel (which is fundamental to the motor operating) is not tested and its components wouldn’t survive in these temperatures.

Pressure sensitive protective equipment

Clause 5.8.6 of BS 8524-1 states, “Pressure-sensitive protective equipment (PSPE). Where pressure-sensitive protective equipment is provided, such as a safety edge, it shall conform to BS EN 12453:2001, 5.1.1.6, and shall stop deployment of the barrier assembly on operation.”

Our opinion is that a fire curtain should always close and that it is much safer to have a ‘light’ curtain in front of the fire curtain to detect obstacles including people. The fire curtain can then audibly warn users in the area to clear the obstruction whilst pausing deployment for a pre-set time. On clearance of the obstacle the fire curtain would fully deploy.

Therefore, this test seems of questionable merit.

BS 8524 descent speed requirement

Operation deployment speeds are not unique to BS 8524-1, being also referred to in product standard ISO 21524. For example, ISO 21524, clause 7.4.1 states, “The active fire curtain shall commence deployment within 10s of receipt of an initiation signal and move to its fire-operational position in all operating modes. The active fire curtains shall have a velocity of not less than 0.03 m/s. Within 2.0 m of floor level, the velocity shall be not more than 0.15 m/s for vertical deployment or 0.3 m/s for horizontal deployment”

ISO 21524 is an excellent product standard for fire curtains and Adexon Fire & Smoke use it for horizontal fire curtains. Unfortunately, as with BS 8524-1, ISO 21524 is not a harmonised standard and hence cannot offer legal compliance to the Construction Products Regulations for vertical fire curtains, hence limiting its use.

Operation deployment speeds are also covered in harmonised standard 12101-1 for smoke curtains, clause 5.4, “Active smoke barrier types ASB1 and ASB2… shall… move… at a velocity range of between 0.06 m/s and 0.3 m/s” and “Active smoke barrier types ASB3 and ASB4… shall have a velocity range of 0.06 m/s and 0.15 m/s”.

Adhering to these guidelines is achieved by designing the motors with a maximum operating speed of 0.3 m/s or 0.15m/s as required, and factory programming the Control Panels.

Impact test or ‘Load resistance’

BS 8524-1:2013, Clause 5.2.1, states “When a specimen of the barrier assembly conforming to Annex C [Fig. 4], C.2.2.2a) is tested for large soft body impact and crowd pressure in accordance with BS 5234-2, having a pendulum drop height set at double that specified for the severe duty (SD) level, the assembly shall remain operable afterwards, and gaps shall not develop between the fabric and beyond the retention device (side guides).”

It is interesting to note, BS 5234-2 is another door test used within BS 8524-1 (along with the main tests such as for fire, BS EN 1634-1, and smoke, BS EN 1634-3), which is at odds with saying, “BS 8524-1 is specific to fire curtains as they act differently to doors”.

However, the BS 5234-2 impact test is hypothetical for fire curtains (whilst being widely promoted as one of the reasons ‘BS 8524-1 is a more robust standard’) as it is designed to measure deformation of a solid surface (partition including door). See Fig. 5.

Here are some key points:

BS 8524-1

  • BS 8524-1 impact test is from BS 5234-2:1992 “Partitions (including matching linings) — Part 2 etc.”
  • It is not an appropriate test for flexible material. It measures deformation of a rigid surface (partitions and doors).
  • It is carried out at room temperature.
  • The ‘Severe Duty’ referenced in BS 8524-1 allows 1-2mm of deformation in the surface of the partition or door. Fire curtain fabrics often aren’t much thicker to start with.
  • The cushioning of the sandbag by the flexible surface and the outcome measured makes this test of no value.

BS EN 16034

  • The horizontal weight test (carried out in the furnace) in BS EN 15269-11 is the correct test method for gauging load resistance, and durability of fabric and retention, including in a fire.
  • BS EN 15269-11 is mandatory under BS EN 16034 if you require an EXAP for larger sizes than the furnace (we advocate only buying fire curtains with third-party certified EXAPs from a Notified Body).
  • EXAPs are the most reliable method of independently certifying sizes larger than the furnace can test e.g. above 4m x 4m. This is universally known and one of the safety benefits of the European standards and classification system.
  • A guide and fabric are installed horizontally in a furnace, with the fabric holding a weight of 50kg (491N) up to100kg (981N), depending on width required.

In summary, load resistance for fire curtains is correctly tested in BS EN 16034 whilst the impact test in BS 8524-1 is another well marketed test that has no value in real life (e.g. along with the hot motor test that doesn’t hot test the control panel – the control panel is required to operate the motors). As well as the BS 8524-1 impact test being an inappropriate test for fire curtains, the most conclusive evidence on it being of no value in real life is the products that have passed it, some of the worst and most unreliable and problematic fire curtains on the market. See more in, The quiet transformation happening in the fire curtain industry9

The simple answer is that BS EN 16034 fire curtains are load tested in accord with BS EN 15269-11 which is the appropriate test for a flexible material and retention system, and especially a fire resistant one as it is done in a furnace.

Under BS EN 16034 it is mandatory to test and certify in accord with the applicable EXAP for fire curtains above the fire tested sizes i.e. fire curtains bigger than the test furnace. In this case the EXAP is done in accord with BS EN 15269-11. No such rigorous or documented controls or checks exist in BS 8524-1 meaning fire curtains larger than the furnace that were historically tested to BS 8524-1 may only have a likelihood assessment that they will work in a fire, of they may have no independent test at all meaning there is no way of knowing if they will work in a fire. Some furnaces are only 3m x 3m meaning a significant volume of BS 8524-1 fire curtains have entered the market in this manner.

The BS 8524-1 impact test is not a correct test for fire curtains; it is a test for measuring deformation of rigid partitions and doors and is not designed for testing flexible materials such as fire curtains.

The flexible fire curtain fabric will cushion the force due to being able to flex meaning the torque of 100Nm applied (or the torque resulting from double the pendulum drop height) is not a rigorous examination of the fire curtain fabric and/ or its retention.

The test implies simulating protecting against a person falling into the curtain and damaging the material, affecting its ability to stop the spread of fire.

However, it is questionable what an impact of 100Nm (or even double) on a flexible surface will assess and achieve as the force is ‘absorbed’ to some extent by the flexible fabric surface and even a full ‘un-cushioned’ 100N is equivalent to less than 12Kgs falling under gravity.

The horizontal weight test is a tougher examination of the durability of the fabric – and it tests the retention system – and is carried out in a fire situation, not just a cold test.

Ultimately, the lack of benefit in the BS 8524-1 impact test is seen in the products on the market that have ‘passed’ the BS 8524-1 impact test and then fail in real-life (jamming solid, tearing, and ripping). If a test allows poor products to pass it, then it is not sufficiently rigorous.

Fixing types and product descriptions

BS 8524 certificates do not include the details of the fixing types or lengths to be used, or the description or specifications of components such as the sizes of the guides or thickness and types of materials.

Even prior to the withdrawal of third-party certification (read more on this in our white paper ‘Fire curtain regulations in the UK’), this lack of detail on BS 8524 certificates meant the products were particularly vulnerable as there was no way the end user could check that they are getting the product details that was originally tested. This is compounded now there is no certified auditing of what is being put on the market.

Without certified auditing, products manufactured to BS 8524 could differ from the original tested specimen in a number of ways, such as changes to the details of fabric retention in the guides, or adjustments to the position and protection of the drive motor in the barrel.

A fundamental shortcoming of the old BS 8524 fire curtain certificates was that they did not tell the end user the maximum size of fire curtains that are tested and certified. For example, the manufacturer could have passed the fire tests with a 3m x 3m fire curtain and yet could be selling fire curtains that are 6m x 6m under the same certificate.

Fixing types and product descriptions

BS 8524 certificates do not include the details of the fixing types or lengths to be used, or the description or specifications of components such as the sizes of the guides or thickness and types of materials.

On the other hand, BS EN 16034 certificates from a Notified Body such as Applus+ include a Technical Annexe as part of the CE marking requirements which clearly states the maximum sizes tested, and other very significant details such as these.

Ancillary equipment testing

BS 8524 requires that any ancillary equipment (obstruction warning devices, switches, and activation devices) that are to be used in conjunction with the fire curtain must be physically tested to ensure they function as expected; this test is not performed under any heat and is conducted in a laboratory setting.

The value and benefits of this laboratory testing are open to debate, as the components used are themselves CE marked and it is the actual on-site installation of the ancillary equipment by the engineer that is critical and must be checked to ensure functionality.

Heat test for switches

BS 8524 stipulates that the switches used to retract the curtain are heated to 68°C for 5 minutes to check that the barrier stays deployed or only retracts once and subsequently re-deploys. As with the hot motor test, it is difficult to see how this test has any relevance to the safety or performance of the fire curtain; the switches would be subjected to far higher temperatures for much longer in a realistic fire scenario.

Specifying how the curtain is to be installed

BS 8524 only specifies that curtains need to be tested in one installation arrangement, and this orientation is not stated anywhere in the publicly available documentation. This is significant because the fire curtain is face fixed to the exterior of the furnace meaning the headbox and guides are only partially exposed to fire.

In practice, if the curtain is fitted the other way round, there is no test evidence that the BS 8524 curtain will provide the required fire performance. There is nothing in the publicly available documentation to say which is the correct way round, and there is nothing to stop it. Obviously, the probability of it happening is 50/50 (fit it the correct orientation or the incorrect orientation). This probability level seems a very significant risk to take with a life safety critical product.

In contrast, on the Applus+ certificates for BS EN 16034, the exact arrangement that the fire curtain is suited to is clearly stated. This stipulation of the installation arrangement is vital to ensuring the system is used in the way that has been tested so it will deliver the declared fire performance.

Gravity fail-safe requirement

BS 8524 tests that the curtain descends in a controlled manner to its fire-operational position even if mains and auxiliary power is removed or in the event of wiring corruption.

It is common practice for all fire safety products to fail in the fire-operational position to ensure fire protection is provided in every eventuality. This is why fire curtains are usually activated by the opening of a normally closed signal; then, if the wire is cut or damaged, the curtain will automatically descend into its operational position.

A gravity fail-safe test is part of most responsible manufacturers’ commissioning, servicing and maintenance procedures, ensuring that each fire curtain descends into its fire-ready position when all power is removed, and this would be a sensible addition to a future revision of BS EN 16034.

Short circuit tests

As described above, BS 8524 requires that the barrier assembly shall fall under gravity to the fire-operational position in a controlled manner, even if there is damage to the motor wire. A plethora of scenarios could damage the motor wire and result in a short circuit, such as remedial works after installation, falling debris or maintenance of other systems.

Some electrical motors can fail to descend under gravity fail-safe or fall in a controlled manner when there is a short. The motor short circuit test in BS 8524 safeguards against these instances.

Switches are also checked to ensure that, if a switch has a short circuit, the barrier will stay deployed or only retreat once and subsequently redeploy. Switches use a normally open circuit that, when closed, signals the control panel to retract the fire curtain up into the open position. This test guards against allowing switches to continuously open and close the curtain if the switch wire is shorted (i.e. the circuit is closed).

While the probability of these specific scenarios materialising is low, their potential impact is significant. Failure to deploy a fire curtain when required could result in severe consequences. For manufacturers without BS 8524, this test can be undertaken separately. This is the route Adexon has taken and recommends all manufacturers to undertake it. It would be a worthy addition to a future revision of BS EN 16034.

Reaction-to-fire test

BS 8524 requires that the curtain fabric used is tested to BS 476-6 and 476-7 and achieves a class 0 or 1 rating to determine the surface spread and propagation of flames. This test challenges the fabric alone and not the entire system.

Reaction-to-fire is a largely superfluous test, as the entire fire curtain system is tested to BS EN 1634-1, where the whole system is subjected to over 1000°C. The reaction-to-fire test may even give customers a false sense of security by neglecting all the other variables inherent in a fire curtain, such as the stitching of the fabric.

CE marking

BS EN 16034 is the only standard for fire curtains that is harmonised and can therefore be CE marked with third-party certification. This is essential for guaranteeing a product’s conformity to EU regulations, particularly for safety, health or environmental requirements.

In contrast, BS 8524 cannot be CE marked as it is not a harmonised standard.

Any product not CE marked with third-party certification has only the manufacturer’s assurance that it will perform as tested.

There is further discussion in a separate article about why, whilst third-party certification is essential, CE marking is critical5, especially for life safety products such as those relating to fire.

5. What to buy?

What should you buy? BS 8524-1 fire curtains? BS EN 16034 fire curtains? Or both?

It is not possible to use both standards for the same product as they conflict. When BS 8524 is revised it should only cover concertina fire curtains and horizontal fire curtains – unless there is a change to BS EN 16034 in the future.

The UK is understandably proud of BS 8524-1:2013, as it was the first dedicated product standard (in the world) for active fire curtains. It probably contributes to how much we have adopted it in the UK. However, there are three or more risk considerations with using BS 8524:

1) BS 8524 third-party certification expired on 9th June 2023, and a new scheme is still TBC.

Using an analogy, the risk here is, “if I made something, I’d tell you it was perfect…”, i.e., everyone says what they make is great. There is no satisfactory answer to overcome this for BS 8524 currently (without back-tracking on what has been held to for many years, that third-party certification for life-safety products is a prerequisite). This means, without third-party certification, you could get something different than what was tested with BS 8524 products.

2) CE marking to BS EN 16034 is legally required under the CPR for vertical fire curtains

The acid test under the CPR is, ‘if a product is covered by a harmonised standard…’ it is legally required to be CE marked to that standard. People may say there are very few prosecutions under the CPR, or that those policing it (Trading Standards and the OPSS) would simply ask the industry if BS EN 16034 applied to vertical fire curtains and that some in the industry would argue in favour of BS 8524, but this is scant comfort.

3) BS 8524-1 allows using BS 476 for a number of tests such as the main fire resistance test. Under the Building Safety Act 2022, BS 476 is being removed from use in favour of the superior European Standards and Classification system. Removing BS 476 is good for safety8.

It is not ok to have fire curtains certified to both standards (if and when certification is available again for BS 8524) as there is a direct conflict such as with the fire test. You may (in the future) get BS 8524 certification that has been achieved using the BS 476 fire testing. This would not comply with BS EN 16034. The legal requirement (and best option, see ‘Why scrapping BS 476 is good for safety’8) is to use BS EN 16034. So, whilst it is safe and legal to have fire curtains compliant only to BS EN 16034, it is neither safe nor legal currently to have vertical fire curtains only compliant to BS 8524.

Hierarchy of considerations when buying

Number 1 has to be legal compliance, and this makes BS EN 16034 the right standard for vertical fire curtains. BS EN 16034 is harmonised and covers vertical fire curtains and hence it is a requirement of the CPR to CE mark to it.

Number 2 consideration when buying life-safety products is third-party certification. The leaders in the industry are unanimous as to the necessity for third-party certification from a UKAS or equivalent accredited Notified Body. For example:

ASFP say, “any passive fire protection system… should be fully backed up by third-party certification for the manufactured product”9.

FIREX say, “We took the decision last year [2022] to make it a condition of exhibiting at FIREX that any manufacturer who provided fire safety products… they needed a third-party approval of the products… we are very, very glued into and locked into third-party approval as a condition… we want visitors to understand that when they come to FIREX”

Third-party certification provides independent accredited Factory Production Control and auditing. Without it, anyone can manufacture products that apparently are the same as the tested specimen but there is no independent and regulated auditing of this.

The last remaining third-party certification for BS 8524-1 expired on 9th June 2023.

The only third-party certification available for fire curtains is:

  • Vertical fire curtains – BS EN 16034
  • Concertina fire curtains – BS EN 16034
  • Horizontal fire curtains – ISO 21524*

* ISO 21524 is the only standard with third-party certification from a Notified Body that specifically covers horizontal fire curtains. As such, due to the unique and intricate design of horizontal fire curtains, we advocate only using ISO 21524 third-party certification for horizontal fire curtains, rather than just using a fire resistance test such as BS EN 1634-1:2014.

This makes BS EN 16034 the safe standard for concertina fire curtains, and ISO 21524 the safe standard for horizontal fire curtains.

This raises the question as to the uses of BS 8524-1, if it isn’t withdrawn.

There are two considerations.

Now, and in the future.

In the future, if BS 8524-1 achieves third-party certification again it can be considered safe for use for those types of fire curtains the new certification covers e.g., concertina and/ or horizontal.

However, lets first look at the status quo (a lot can happen in the future that wasn’t planned, and the best made plans don’t always come to fruition).

Where are we today with BS 8524-1?

As it stands, without offering a route to compliance with the CPR for vertical fire curtains, and without being able to offer valid third-party certification, BS 8524-1 cannot be used.

As you will have seen throughout this white paper, there are pluses and minuses to BS 8524, and quite a bit of cross-over with BS EN 16034 for the essential aspects.

In the future…

Let’s consider the scenario where BS 8524-1 is successfully revised in the future and achieves the backing of a Notified Body, and third-party certification is again available for it; could we then use BS 8524-1 on its own?

Well, the answer is, No, for vertical fire curtains; vertical fire curtains have to be CE marked to BS EN 16034. The answer is also likely, No, for horizontal fire curtains as these are a very niche market and there may not be enough demand to commercially justify a Notified Body developing a BS 8524 scheme for them.

This leaves concertina fire curtains as the only configuration of fire curtain that could potentially be used for BS 8524-1 on its own, even when the new and revised BS 8524-1 is available, and a scheme has been created and accredited and certification undertaken.

Pros and cons

Finally, we can look at the pros and cons of the two standards in comparison but this should not influence the necessity for legal compliance and third-party certification.

Having summarised where you should and shouldn’t use BS 8524-1 and BS EN 16034, let’s look quickly at the merits or otherwise of the two standards in comparison.

BS 8524 has three additional beneficial tests/ stipulations* which BS EN 16034 doesn’t have:

  • the ‘Gravity fail-safe requirement’,
  • ‘Short circuit tests’, and
  • ‘Descent speed requirement’.

Adexon advocates all responsible manufacturers to undertake these tests whether or not they are using BS 8524.

On the flip side, BS 8524 has a number of downsides which BS EN 16034 doesn’t have. These downsides of BS 8524-1 vary in seriousness and potential liability.

Downsides of BS 8524 when compared with BS EN 16034 include:

  • allows BS 476 testing;
  • allows ‘likelihood’ fire performance evaluations;
  • superfluous and arguably dangerous tests:
    • Hot motor test;
    • Pressure sensitive protective equipment;
    • Ancillary equipment testing;
    • Heat test for switches; and
    • Reaction-to-fire test;
  • unable to comply with the legal requirements of the CPR CE/ UKCA mark;
  • lack of traceability and transparency of paperwork i.e., no public details on:
    • product dimensions tested and certified;
    • fixings used;
    • materials or components tested; and
    • orientation tested (it is 50/50 it is the right way round);

*we advocate these tests be taken independently and the descent speed be adhered to by designing the motors with a maximum operating speed of 0.3 m/s or 0.15m/s as required, and factory programming the Control Panels.

Some of these downsides may be corrected in a new and revised version of BS 8524-1 which we would welcome.

6. Summary of key points to consider

Some of the key points from the above:

  • “standards aren’t the same as regulations and following a standard doesn’t guarantee that you’re within the relevant laws”1 (BSi)
  • BS EN 16034 is the only harmonised standard available for fire curtains and hence the only standard available to CE mark fire curtains to.
  • ‘Compliance with a British Standard cannot confer immunity from legal obligations‘ (BSi)
  • BS 8524 is a national standard that conflicts with BS EN 16034 as referred to in the harmonised standard foreword of the BSi publication of BS EN 16034. This means it is not a question of using BS 8524 in an ancillary capacity to ‘compliment’ BS EN 16034.
  • BS 8524 allows the use of BS 476 tests which are inferior to the European counterparts. For example, a fire curtain with a 60-minute integrity rating under BS 476 may only achieve a 50-minute integrity rating in a European fire test. This is because the European test uses a plate thermometer which means up to 30% greater thermal exposure. See more on our video, ‘5 reasons why scrapping BS 476 is good for safety’8.
  • BS 8524 certificates do not include critical product details. Even prior to the withdrawal of third-party certification this meant the products were particularly vulnerable as there was no way the end user could check that they are getting the product details that was originally tested. This is compounded now there is no certified auditing of what is being put on the market.
  • Without certified auditing, products manufactured to BS 8524 could differ from the original tested specimen in a number of ways, such as changes to the details of fabric retention in the guides, or adjustments to the position and protection of the drive motor in the barrel.
  • BS 8524 fire curtain certificates do not tell the end user the maximum size of fire curtains that are tested and certified. For example, the manufacturer could have passed the fire tests with a 3m x 3m fire curtain and yet could be selling fire curtains that are 8m x 3m under the same certificate.
  • BS EN 16034 certificates from a Notified Body such as Applus+ include a Technical Annexe as part of the CE marking requirements which clearly states the maximum sizes and other significant details.
  • BS 8524 specifies that curtains need to be tested in one installation arrangement but this orientation is not stated on the certification. If the curtain is fitted the other way round, there is no test evidence that the BS 8524 curtain will provide the required fire performance. The probability of it happening is 50/50 (fit it the correct orientation or the incorrect orientation). This probability level is a very significant risk to take with a life safety critical product.
  • It is not advisable (even if it were possible) to have fire curtains ‘compliant’ to both standards. Whilst it is safe and legal to have fire curtains compliant only to BS EN 16034, it is neither safe nor legal to have fire curtains only compliant to BS 8524.
  • The Applus+ certificates for BS EN 16034 state the exact arrangement that the fire curtain is suited to which ensures the system is used in the way it has been tested.
  • The BS 8524 hot motor test, with the capability to operate the motor at 400°, is significantly more dangerous than any safety merits it may provide. It is also not true to real life as the Control Panel that operates the motors are not tested.
  • The BS 8524 pressure sensitive protective equipment test seems superfluous and somewhat questionable
  • The reaction-to-fire test may give customers a false sense of security by neglecting all the other variables inherent in a fire curtain, such as the stitching of the fabric.

7. Conclusion

The No.1 consideration when buying life-safety products is legal compliance. This makes CE marking to BS EN 16034 mandatory for vertical fire curtains since 1st November 2019.

No.2 consideration when buying life-safety products is third-party certification. The industry leaders are unanimous as to the importance of this. This makes BS EN 16034 the safe standard for concertina fire curtains, and ISO 21524 the safe standard for horizontal fire curtains.

As it stands, without offering a route to compliance with the CPR for vertical fire curtains, and without being able to offer valid third-party certification, BS 8524-1 cannot be used. In the future it may be possible to use it for concertina fire curtains and horizontal fire curtains (if schemes are created for it by a Notified Body when it gets revised).

Consider that BS 8524 allows BS 476 testing; BS 476 testing is being removed from use by the Building Safety Act as it is inferior to the European Standards and Classification system. See more on our video, ‘5 reasons why scrapping BS 476 is good for safety’8.

In the future, if third-party certification is again available for a new and revised BS 8524-1, could we then use BS 8524-1 on its own?

Well, the answer is ‘No’ for vertical fire curtains; vertical fire curtains have to be CE marked to BS EN 16034. The answer is also likely ‘No’ for horizontal fire curtains as these are a very niche market and there may not be enough demand to commercially justify a Notified Body developing a scheme for BS 8524 horizontal fire curtains. This is accentuated with ISO 21524 already being in use for horizontal fire curtains.

This leaves concertina fire curtains as the only likely configuration of fire curtain that could potentially be used for BS 8524-1 in the future when the new and revised BS 8524-1 is available, and a scheme has been created and accredited and certification undertaken.

Important: Old BS 8524 certification is absent important details. As an example, you could buy a BS 8524 fire curtain that is 8m x 3m in size and there is nothing on the public documentation to tell you that it has only been tested to 3m x 3m. This could have unknown consequences in a fire.

In contrast, BS EN 16034 provides traceability, assurance, and transparency with third-party certification, and CE marking for vertical fire curtains.

From the detailed discussion of the standards above we can see that BS EN 16034 is legally compliant on its own, has valid third-party certification, and includes the essential performances that the end-user needs from a fire curtain. It also has a simple and proven structure that makes the explicit details readily available for everyone to see and relies wholly on the superior European Standards and Classification system.

This white paper was written by the team at Adexon Fire & Smoke in October 2022 (revised 28th June 2023).

It includes the views of the Adexon team and its intention is to raise awareness and standards in the fire safety industry.

If you have a question for the team or would like to give feedback to this white paper or find out more, please get in touch.

We have a free RIBA CPD on active fire and smoke curtains, either in-person or online, you can book online11 (or contact us).

And/ or keep up to date on regulations and standards around fire curtains with our ‘Fire Safety Insights monthly newsletter12.

8. Additional reading

For an example of going above and beyond legal compliance, read, ‘Are cold smoke seals in fire curtains a cause for concern?’6

If you are interested in impact testing, read why the design of the fabric retention and the durability of fire curtain designs is paramount, ‘Fabric retention design on fire curtains – why does it matter?’7

If you would like a deep dive read on the regulations applicable to fire curtains, you can find this in our white paper ‘Fire curtain regulations in the UK’2

9. References

1 Standards and regulation (no date) BSI. Available at: https://www.bsigroup.com/en-GB/standards/Information-about-standards/standards-and-regulation/#:~:text=It%20certainly%20speaks%20volumes%20about,the%20lifetime%20of%20the%20standard.

2 Adexon Team (2023) Fire curtain regulations in the UK, Adexon Resources. Available at: https://www.adexon-uk.com/whitepaper/fire-curtain-regulations-in-uk/.

3 ASFP (2021) ASFP advisory note.pdf, Zoho WorkDrive. Available at: https://workdrive.zohopublic.eu/file/a7yip4e4df488d7d44a76a28d2d556e110def.

4 Willi, J.M., Horn, G.P. and Madrzykowski, D. (2016) Characterizing a firefighter’s immediate thermal environment in live-fire training scenarios – fire technology, SpringerLink. Available at: https://link.springer.com/article/10.1007/s10694-015-0555-1.

5 Adexon Team (2023) CE switchover postponed to 2025 – and its application to fire curtains. , Adexon. Available at: https://www.adexon-uk.com/article/ce-switchover-postponed/.

6 Adexon Team (2023) Are cold smoke seals in fire curtains a cause for concern? , Adexon. Available at: https://www.adexon-uk.com/article/cold-smoke-seals-in-a-fire/.

7 Adexon Team (2023) Active fire curtain maintenance – and the 3 reasons fabric retention design matters, Adexon. Available at: https://www.adexon-uk.com/article/why-fabric-retention-design-on-fire-smoke-curtains-matters-a-lot/ .

8 Adexon Team (2023) Why scrapping BS476 is good for safety, Adexon. Available at: https://www.adexon-uk.com/video/why-scrapping-bs476-is-good-for-safety/.

9Adexon Team (2023) The quiet transformation happening in the fire curtain industry (2023) Adexon. Available at: https://www.adexon-uk.com/articles/the-quiet-transformation-happening-in-the-fire-curtain-industry/ (Accessed: 29 December 2023).

10 Adexon Team (2023) Safety is the standard – a detailed look at British standard BS 8524 and why it can no longer be used for fire curtains., Adexon. Available at: https://www.adexon-uk.com/whitepaper/safety-is-the-standard/.

11 RIBA accredited CPD course (2024) Adexon. Available at: https://www.adexon-uk.com/riba-accredited-cpd-course/ (Accessed: 08 July 2024).

12 Adexon Team (2023) Fire safety insights, Adexon Newsletter. Available at: https://bit.ly/AdexonNews (Accessed: 09 November 2023).

13 Adexon Team (2023) The dangers of the hot motor test in BS 8524-1:2013, Adexon. Available at: https://www.adexon-uk.com/the-dangers-of-the-hot-motor-test/ (Accessed: 30 August 2023).

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