Industrial Fire & Thermal Asset Protection
  • Certified and tested products to international standards

The Challenge of Passive Fire Protection

MCL was originally incorporated in 1992. The company’s purpose was to manufacture fire seals under license for a leading supplier of the period. During the following years the company changed ownership and in 1994 MCL started on its journey to develop and test its own brand of passive fire protection systems, which we named “Firetex”.

The original specification of passive fire protection targeted two significant problem areas highlighted by engineers dedicated to offshore oil and gas fields.

The first of these problems was to protect the pipe and sleeve orifice formed when a pipe passed through decks and bulkheads, primarily in steel structures.

The second problem was to protect gaps between steel modules that may have been retrospectively installed following platform upgrades.

In the case of new living quarters, for example, engineers deliberately allowed these modules to sit on anti-vibration mounts in an effort to reduce the transfer of noise and vibration.

In these cases, the passive fire protection had to be flexible and installed after the installation of the pipes and modules. Testing was conducted following the rules of Safety of Life at Sea (SOLAS) amplified by the International Maritime Organisation.

MCL was not alone in the development of its passive fire protection systems. The regulators were also developing international testing standards that better matched the purpose of the passive fire protection.

Jet Fire Testing Standard

A good example of this can be seen in the development of the jet fire testing standard. The original standard OTI 95634 was later revised to ISO 22899-1:2007. Within these standards, a test specimen was placed on a single pipe horizontally in front of a jet fire at one-metre distance.

Under the test conditions, it was impossible to review the back of the test specimen during testing for a clear pass or fail indication. Results were judged on the data recorded by thermocouples placed in set locations under the specimen. Any temperature spikes recorded by the thermocouples would demonstrate the seal had been breached by hot gases. In addition, a post-mortem of the sample would be conducted after it had cooled and any observations recorded.

The updated standard ISO 22899-2:2013 was later released. This allowed full scale pipe penetrations seals to be tested in purpose-built hardware mimicking actual site conditions.

MCL used this opportunity to test seals to the new test standard, which dictated a pipe of 10 inch outside diameter and sleeve of 14 inch outside diameter were used. In addition, we also tested other arrangements, which included 36” bends, multiple pipes and “non-standard” configurations to better prove the range of protection our seals can offer.

During testing, the fire seal’s performance can now be visually monitored, and any failure identified in real time from the back of the seal.

In addition to the improved test layout, the jet fire is aimed at the fire seal’s weakest point. This is considered to be seal’s overlap area, which is an integral part of the retrofitted design.

While resisting the heat and flame impingements, the piping would now be free to move in relation to the bulkhead as it warped and buckled under heat loading. Our flexible seal absorbing the large movements during the tests.

In our hydrocarbon testing where the test specimen was fixed to a 3-metre x 3 metre bulkhead, we recorded warping of up to 100 mm in any direction, the fire seals remaining functional during the entire test.

In the image we can see the jet fire impinging on the opposite side of a 36” diameter circular penetration, the bulkhead and pipe glowing red indicating a steel temperature of around 800 degrees Celsius had been reached, the flame temperature calculated at around 1100 degrees Celsius directed toward on the overlap of the fire seal.

To aid maintenance and inspection, the latest range of seals does not require the overlap bonding with adhesive or sealant. This means seals fitted today can be carefully removed for inspection and maintenance purposes quickly and easily at a later date with no fuss or mess.

This design philosophy is carried throughout our new range of fire seals from H0 to J0 ratings.

We test our products at various locations around Europe. Each test facility is independently inspected by third party underwriters to ensure testing meets the required standard, in the case of hydrocarbon testing, the test centre must meet the standard is ISO 17025. Only after independent scrutiny is a test facility allowed to perform a test which can be later used for evidence of Type Approval.

The industry has many fire-resistant ratings, these can be characterised by a fire’s intensity. Commonly, “A” ratings are considered for household equipment, modules and gas turbine enclosures. “H” rating for industrial equipment where oil and gas is used in process close by, and “J” rating where pressurise hydrocarbon fuels are used in the immediate vicinity.

Our fire seals are tested against fires with heat fluxes between 150kw/m2 up to 300kw/m2

  • For cellulosic testing, the recognised test duration is 1 hour.
  • For hydrocarbon testing, the recognised test duration is 2 hours.
  • For Jet fire testing, the test duration can vary, however our systems are tested from 30 minutes and up to 2 hours.

In addition to fire-resistant specifications our clients also request other forms of protection, possibly the most arduous requirement is for our seals to resist blast loading.

What is blast loading? It is most easily described as a force applied to a seal immediately after an explosion. Given the right mixture of flammable gas, air plus an ignition source, the resultant flame will accelerate with exceptional speed outwards until all the flammable gas is consumed. This wave of flame and heat travels at incredible speed, creating a wave of pressure that is strong enough to do incredible damage to anything in its way.

This blast wave can be mathematically calculated in advance and the actual blast size and duration recorded in real time in specialised testing laboratories. This allows our engineers the possibility to design & test seals to resist predicted blast resistance levels.

MCL Unitex has tested a wide range of fire seal shapes and sizes in front of blasts of up to 2.5 Bar peak pressure. So why is blast level important? Well, we need to ensure that our seal systems stays in place in the event of an explosion, to ensure they can go on to give the passive fire protection they are designed to offer.

Flexible Product Design

Our flexible product design is the key component of our passive fire protection system and this separates MCL from the many other systems available, if an item requires a certain flexibility we build this into the product. All our systems are retrofittable which contributes to the safe working operation and allowable maintenance of the item being protected.

As a company that prepares specialist equipment which is often unique in design, it should come as no surprise the company structure emphasises its strengths through its relationships with its clients. From initial product concept, through design and specification to manufacturing and delivery we communicate the process with you every step of the way.

The company ethos is built around the knowledge our products may one day help to save lives. We understand every life is special and that every item we make has to be made to the highest standard. There are no shortcuts or half measures that can be taken.

Often, we are tasked to make full scale models in our workshops of equipment and services. It is from these models we manufacture the items you need. For simpler items, as a minimum, there will be a detailed drawing or calculation sheet to enable the manufacture and later inspection of the product.

All of this work is completed by time served machinists. There are no special machines preparing these items at the push of a button. Every item we make is crafted, sewn, inspected and finally packed by hand.

Over the course of time, we have also prepared our products to protect against non-fire rated applications. By far the most common request is to offer some protection from rain. For these requests, we have offered a rain jacket in the industry standard silicone coated glass cloth built to faithfully copy the size and shape of the fire-resistant item.

In addition, we have also been requested to protect from temperatures down to -186 degrees Celsius. At these temperatures, even 10 mm thick carbon steel can crack, such is the severity of temperature change. However, we have managed to not only find a solution but also test it for 1 hour’s resistance to liquid nitrogen with no negative effect from the huge change in temperature post cooling.  We then took the tested seal and completed a 60-minute jet fire test before it became non-operational.

Taking a look into the spring and summer of 2023, MCL will be pushing the boundaries of fire sealing further, building on our successful H0 testing.

Once the testing has been successfully completed, MCL will have updated and revalidated its entire range of pipe penetration sealing products, which equates to more than a dozen full-scale tests and literally hundreds of samples of prototypes made.

This brings me, Alan Aslin, Sales Manager for MCL Unitex to ask a question of my own. “What passive fire protection will you need next?”

We can see the market is moving towards new power technologies, and we have concerns for hydrogen and battery powered products. If you are working in these sectors and need a passive fire solution, our team at MCL Unitex is waiting to partner with you.

Our portfolio of products covers the following categories. H0, H120, Jet fire resistance from 44 to 120 minutes dependent on numerous factors which can be confirmed on application.