Decorative Fire Protection for Internal Linings
Decorative Fire Protection For Internal Linings - PPG
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For this video CPD, we will be discussing the importance and specification of decorative fire protection for internal linings.
This presentation will cover these key areas:
- The importance of flame-retardant decorative coatings
- The creation and growth of fire
- How different paints react to fire
- Current building regulations and British Standards
- Testing flame-retardant and intumescent paints
- Specifying the right fire-protective coating
- Johnstone’s Trade’s range of fire protection paints
The Importance of Flame-retardant Decorative Coatings
So let’s start by looking at why flame-retardant paint coatings are important.
Fire can have devastating consequences for people, businesses, and communities, resulting in both financial loss and the potential for injuries or death.
The Cost of Fire
According to the Association of British Insurers, fire is one of the most expensive property insurance claims in the UK, with £1.3 billion being paid out to customers during 2018. That’s more than £3.5 million per day.
The overall economic impact of fire is difficult to calculate, and statistics are difficult to find. In 2008, it was estimated that fires cost the UK economy around £8.3 billion, and in 2004, the Chief Fire Officers' Association estimated that 60% of private businesses never recover from a fire, resulting in further economic impact and job losses.
Careful specification of all aspects of a building - from fire detection systems and fire doors to fire-protective paints - can help to reduce the risk of fire and its associated costs.
Fire and Rescue Incident Statistics
Fire incidents are broadly categorised based on the location, severity, and risk levels of the fire, as well as the scale of response needed to contain it and broadly fall into one of three categories:
- Primary fire - this includes all fires in buildings, vehicles and most outdoor structures, or any fire involving casualties, rescues or fires attended by five or more pumping appliances.
- Secondary fire - usually small outdoor fires that do not involve people or property.
- Chimney fire - any fires in buildings where the fire was contained within the chimney structure.
Today, we are focussing on primary fires, as this category includes fires in buildings. There were 88,120 primary fires in England, Scotland and Wales in 2018/19, compared to 89,267 the previous year. As you can see from the graph, the number of primary fire incidents is on a gradual downward trend.
Fire can lead to terrible consequences for the people involved. In 2018/19, 8,750 people were injured due to fire, with 662 hospitalised for severe injuries. Another 318 sadly lost their lives.
Reducing the spread of flame is critical in the early stages of a fire - as this buys time for building occupants, giving them an opportunity to evacuate safely, and allowing additional time for the fire crews to arrive.
How can Decorative Coatings Help?
Based on the statistics we’ve just seen, the need for fire suppression is clear. While no single building or decorating product will be able to prevent a fire all on its own, the different elements of a structure can work together to prevent or slow the spread of fire.
The term “internal lining” relates to materials forming partitions, ceilings or any other internal structures.
Walls and ceilings are major contributors to spreading fire in buildings. Since decorative coatings are the outermost layer of an internal lining, they can act as the first line of defence against fire, protecting the rest of the structure underneath.
While extinguishing a fire would be preferable, it’s not always feasible. In these cases, delaying the spread of flame can save lives by allowing more time for a safe evacuation. It can also help to minimise damage and the intensity of the blaze before fire crews arrive.
Maintaining the Golden Thread of Fire Safety
A key challenge when it comes to fire safety is maintaining design intent throughout the build and continuing it after construction.
The concept of a "golden thread" of information is one that is gaining traction within the construction industry. The term describes an accurate and up-to-date record of information about a building - how it is designed, built and maintained, providing a clear trail of accountability and also helping specifiers ensure that the original design specifications match the finished result. It should also go further, tracking ongoing maintenance to ensure the original design intent is preserved, even years later.
When it comes to fire safety, following the golden thread is extremely important. After all, maintaining intended performance throughout the entire life of the building could save lives in the case of fire.
For example, architects may specify a fire-limiting decorative paint - but will that coating actually get used months later in the decorating phase? Beyond that, what happens in five years when it’s time for redecoration?
Even if a new building meets the fire safety requirements set out in the Building Regulations, changes over time can diminish the fire protection, or eliminate it entirely. When redecorating or refurbishment happens later in the building’s lifecycle, decorators and maintenance teams may not be aware that the existing paint is a flame-resistant coating and elect to use a conventional paint instead.
What’s more, build-up of conventional paint through years of redecoration could reduce the fire classification. Should a fire occur in such a situation, it’s possible that the paint coatings could allow rapid spread of flame across the surface, thus reducing escape times and contributing to a more intense fire.
Maintaining the golden thread is a significant challenge - and the construction industry is still trying to figure it out. There are currently several projects trying different methods, but these mainly cover the design and construction phases. Whole lifecycle management covering handover, maintenance, renovation and demolition is more complicated.
The 2016 BIM mandate, which required public sector construction projects to use BIM was a good first step, and many experts are calling for additional government intervention to strengthen the golden thread.
Improving awareness and training is always beneficial - especially in terms of building management, maintenance and decoration. Effective methods of doing this are still being explored.
The Creation and Growth of Fire
What is fire?
Technically speaking, fire is a chemical reaction. It comprises the rapid oxidation of a material through combustion. It releases heat, light and various reaction products.
The Fire Triangle
There are three elements required for a fire to ignite - this is known as the fire triangle:
- Heat - This can be a flame, sparks or some sort of radiation. According to national statistics, the most common source of ignition for primary fires is cooking appliances.
- Oxygen - From the air.
- Fuel - Anything combustible. In the built environment, this can be anything from timber flooring to walls, furniture and fabrics.
Only when you have all three elements can fire be created.
Fire protection products - such as fire-retardant or intumescent paints - work by preventing these three elements from working together. This can help to slow the growth of the fire, giving more time for people to escape safely and for the fire and rescue services to arrive.
The Three Stages of Fire
There are three stages of fire:
- The initial stage, or “growth” - this is when the fuel starts to burn.
- The “steady state” - this is also when it reaches its peak.
- The decay phase - this is when there is no more fuel to burn, and the fire intensity begins to fall. The gradual process of the fire extinguishing starts to take place.
Flame retardant coatings are designed to extend the time taken to ignite the fuel and increase the time required to reach the second stage of the fire.
The stage that flame retardant coatings are only of real benefit is at the growth stage. The reason for this is that the coatings are designed purely to reduce the growth of fire and hopefully allow extra timefor evacuation before the fire brigade arrives.
If the fire is not suppressed at the initial state, once it reaches the steady state, only conventional firefighting methods are effective.
How Different Paints React to Fire
There are two main options when it comes to decorative fire protection - flame-retardant coatings and intumescent coatings. They work against the fire in different ways. First, let’s look at how conventional paint reacts to fire, then we’ll look at the differences between fire-retardant and intumescent paints.
How Conventional Paints React to Fire
Conventional paint systems tend to allow heat to travel through the face of the coating. This means heat is applied directly onto the decorated substrate.
As a consequence, the surface rapidly heats up.
The surface then becomes the fuel and starts stage one of the fire.
How Flame Retardant Paint Works
When exposed to heat, flame retardant paints produce a non-flammable gas, which reduces the amount of oxygen on the surface. Depending on the coating, it may also produce moisture.
The limiting of oxygen and potential addition of moisture work to stifle the fire, slowing its spread and sometimes extinguishing it entirely.
How Intumescent Paints Work
These are also sometimes called fire-resistant paints.
Intumescents work by creating a physical barrier between the fuel, anything which is combustible, and the source of heat or where ignition occurs.
If for a minute we think of a pie crust being baked in the oven and how it forms by swelling and expanding, this is exactly how intumescents react when in contact with the heat source. They insulate the surface by forming foamed carbon char, which can also be called a sacrifice barrier.
As the surface is subjected to radiant heat, the intumescent layer starts to swell, protecting the substrate.
When fully exposed, the intumescent prevents the heat getting through to the substrate.
Flame-Retardant Paint vs Intumescent Paint
So Let’s recap.
Going back to the fire triangle, removing one of the elements stops the fire. Decorative coatings can’t completely remove the elements, but they can suppress them, slowing the spread of fire and sometimes extinguishing it.
Flame-retardant paints do this by diluting the source of oxygen, thus slowing the spread of fire.
Intumescent paints create a barrier of carbon char around the fuel, insulating it from the heat, so it takes longer to ignite.
Current Legislation and Standards
The list of regulations, legislation and requirements for fire protection in buildings is extensive, and there are more than 50 British Standards covering the topic. Here, we’ll quickly look at some of the main documents in relation to internal linings - to help you understand a specifier's obligations and ensure that golden thread of fire safety is maintained.
Fire Safety Legislation
There are two main sets of general fire safety legislation. In England and Wales, it’s the Regulatory Reform Fire Safety Order 2005 - also known as the RRFSO or RRO.
In Scotland, the general fire safety requirements are covered in Part 3 of the Scotland Fire Act 2005 and supported by the Fire Safety in Scotland Regulations 2006.
Whichever nation you’re looking at, this legislation details the laws surrounding fire safety, fire safety duties and responsibilities. This includes the duty of care for building designers, local authorities, housing associations, building owners and facilities managers to build and maintain premises that minimise fire risk.
As part of this duty of care, landlords and building owners are responsible for carrying out their own risk assessments.
Building Regulations Part B: Fire
Building Regulations Part B covers all aspects of fire protection, including means of warning and escape, internal and external fire spread and ensuring access for the fire services. There are two volumes of the Approved Document: Volume 1 is for dwellings and Volume 2 is for all other buildings.
In regards to internal linings, Part B2, section 6 states that the linings should inhibit the spread of flame within the building by resisting the spread of flame over the surface and, if having ignited, have a “reasonable rate” of fire growth. It also specifies the required fire classification for different areas of a building.
Until recently, Part B specified that building elements needed to be tested according to criteria set out in BS 476 parts 6 and 7. This resulted in the Class 0 or Class 1 rating system that we are all familiar with.
- Part 6 is the fire propagation test. It is a pass/fail test that measures the amount of heat released when the product is burned.
- Part 7 produces a fire rating of Class 1, 2, 3 or 4, depending on how far a flame travels over a coated surface. Class 1 is the best rating.
- To achieve Class 0, a product must pass Part 6 and achieve Class 1 in Part 7.
However, the drawback of this system is that it did not provide a thorough description of a product’s fire performance. Specifically, it omitted information about smoke and burning droplets.
Part B now uses the classification system set out in BS EN 13501-1, and up to five tests may need to be carried out on products to get a classification through this system. These are described by the following standards, which we’ll discuss in more detail in a few minutes:
- BS EN ISO 1182 - Non-combustibility test
- BS EN ISO 1716 - Heat of combustion test
- BS EN 13823 - Single-burning item test
- BS EN ISO 9239-1 - Radiant panel test for floorings only
- BS EN ISO 11925-2 - Single-flame source test
The table here shows some of the required classifications for non-dwellings. These classifications indicate the combustibility of a product using a letter rating from A for non-combustible, to F for combusts easily, followed by the smoke rating as S and burning droplets as D.
A table in Appendix B of Approved Document B provides a useful transposition from the old classification system to the new one. However, this can only be used as a guide, since the classifications do not automatically equate to each other. This is because as the old testing methods did not test for smoke or burning droplets.
BS 9999 is the code of practice for fire safety in the design, management and use of buildings. It is aimed at designers and architects and provides a best-practice framework for fire safety, approaching the subject in a holistic way.
BS 9991 is similar, but with a focus on residential buildings.
Testing Flame-Retardant and Intumescent Paints
How do we know that flame-retardant and intumescent paints work? The answer is simple: we test them.
The Importance of Fire Testing
Independent testing of fire performance is crucial.
From a manufacturer’s perspective, it’s essential for ensuring our products do what they’re supposed to do.
For specifiers, testing demonstrates that the products used will contribute to the overall fire performance of the building.
For end users, testing ensures that the fire protection products used will behave as expected during a fire situation. This improves safety for building occupants and gives them peace of mind.
It’s also essential for ensuring that legal obligations are met - following that golden thread that we talked about earlier.
What Makes a Good Test?
Using a consistent and reliable testing procedure, that’s carried out by a third party helps to ensure that products are fit for purpose and will perform as expected in a fire situation.
There are many third-party companies that will carry out testing. Examples include Warrington Fire Research Centre and the British Research Establishment.
What Fire Tests are Required for Internal Linings?
As we’ve already discussed, the minimum fire performance classification for internal linings will depend on the location of the lining - and the requirements are set out in the Approved Document B. To get a BS EN 13501-1 classification, up to five tests may need to be carried out. These are:
- BS EN ISO 1182 - Non-combustibility test
- BS EN ISO 1716 - Heat of combustion test
- BS EN 13823 - Single-burning item test
- BS EN ISO 9239-1 - Radiant panel test for floorings only
- BS EN ISO 11925-2 - Single-flame source test
Tests Required for BS EN 13501-01 Classification
For the BS EN ISO 1182 - Non-combustibility test - A sample is placed in a furnace at 750°C to identify how the product will or will not contribute to a fire.
For BS EN ISO 1716 - Heat of combustion test specimens are burned under specific conditions, using an apparatus known as an oxygen bomb, to determine its calorific value.
Whilst the BS EN 13823 - Single-burning item test involves subjecting the test specimens to conditions similar to a wastepaper basket on fire. During the test, a number of parameters are measured, including heat release, smoke, lateral flame spread and the falling of flaming particles or droplets.
And finally the final two tests are BS EN ISO 9239-1 - Radiant panel test for floorings only – which is designed to simulate the conditions experienced by a flooring, or floor coating, in a room or corridor during the early stages of a fire.
And BS EN ISO 11925-2 - Single-flame source test – and this test determines the ignitability of a vertically mounted test specimen when a small flame is applied to its surface and/or one of its edges.
Specifying The Right Fire-Protection Coatings
So how do you specify the right fire-protective coating?
How to Know You're Specifying the Right Coating
Is it the right product for the project?
The correct product should:
- Have a suitable fire classification
- Provide the desired type of fire suppression
- Be suitable for use on the substrate in question
Is it from a reliable source?
A responsible manufacturer should provide:
- Test results demonstrating product performance
- Written technical specifications and guidance
- Pre- and post- technical assistance
- Material quantities - certificate of supply
Specification: Flame-Retardant or Intumescent?
Choosing between intumescent and flame retardant simply comes down to whether you’re working on a new-build project, or an existing surface that’s not very aged, or a refurbishment.
In a new-build situation, or on a surface that hasn’t aged much, flame-retardant coatings are the best choice. Since the coatings will be going on a fresh surface, or a surface that’s in good condition, you can enjoy the benefits of quick and easy application, with excellent fire performance when complete.
Flame retardant coatings may be suitable for some refurbishment projects. But these projects are likely to have a build-up of existing coatings - sometimes in excess of ten layers and with a combination of solvent- and water-based coatings. If this is the case, an intumescent coating is the right option, as it will sufficiently cover up all of those old layers, as long as there’s good adhesion. The downside of an intumescent coating is that it is a four-layer process - meaning it’s more expensive and it takes longer to apply. However, applying those layers will probably be easier than stripping away old paint, and the result will be a Class 0 fire rating.
Surface compatibility on Previously Painted Surfaces
To ensure flame retardant/intumescent paint coatings achieve optimum protection, it is important that the building and existing surfaces are inspected in order to recommend the correct system is applied, following that golden thread again.
For each project, it is essential to identify surface conditions via:
- Historical painting records
- Current surface conditions
- Existing factors - such as exposure to external elements
- On-site flake analysis and adhesion testing
Surface Compatibility - Flake Analysis
There are two tests to ascertain the condition of existing coatings:
The first is flake analysis. This measures the depth and number of paint layers on an existing surface.
Flake analysis is a form of destructive testing and if carried out, it has to be done so that the existing coating and surfaces are not disturbed or loosened, which could lead to future failure.
Surface Compatibility - Adhesion Test
The second test is the adhesion test. It measures the adhesion level of the paint layers on an existing surface. A surface deemed to have good adhesion is suitable to apply flame-retardant coatings, while a surface with poor adhesion will have to be stripped first.
There are a number of adhesion tests that can be carried out. These include:
- ASTM D 3359
- ASTM D 4541
- BS EN ISO 4624
- BS EN ISO 2409 - The crosscut adhesion test. This test should be carried out for an overview analysis, but it is deemed unacceptable on heavily decorated textured coatings with multiple existing paint layers.
Before we move on to the types of paint, let’s quickly go over everything we’ve covered so far.
- The creation and growth of fire requires heat, fuel and oxygen.
- Fire-protective coatings are designed to slow the spread of fire by reducing one of the elements needed for fire. This gives additional time for evacuation and arrival of rescue services.
- Fire-retardant paints reduce oxygen availability, while intumescent coatings form an insulating barrier to reduce heat reaching the fuel.
- Fire protection requirements are laid out in the Building Regulations Part B.
- Extensive testing is carried out on all fire-protective coatings, helping to ensure those responsible meet their duty of care.
- Surface tests should also be carried out when painting over existing surfaces, as the build-up of previous paint can contribute to the spread of flame.
- Maintaining the golden thread is important to ensure design intent matches reality.
Johnstone's Trade's Range of Fire Protection Paints
Now, I’d like to introduce you to Johnstone’s Trade Paints and the fire-protection solutions we can provide.
PPG Architectural Coatings: Your partner in paints and coatings
PPG is a global leader in paints, coatings and materials. We operate in more than 70 countries with 150 manufacturing locations. We employ over 47,000 employees worldwide.
Our primary market is the architectural coatings market, serving architects, engineers and painters with a total coatings solution from decorative finishes and floor coatings to EWI systems and protective coatings. We also serve a variety of other industries, including construction, consumer products, industrial and transportation.
All products manufactured by PPG Architectural Coatings UK & Ireland are manufactured under a quality management system that complies with the requirements of ISO 9001:2015, under certificate number FM 01265 approved by the BSI.
We are also certified to ISO 14001 standard for environmental management to ensure environmental impact is being measured and improved and quality management systems are in place across all departments.
Support services for specifiers
We also offer a comprehensive range of support services for specifiers. Our team is available to provide advice and assistance throughout the specification process.
We can provide custom-written specifications in formats to suit you including Word, PDF, NBS CAWS and Uniclass 2015 format. We can also work with you in NBS Chorus.
We are also members of the RIBA CPD Providers Network.
Flame-Retardant and Intumescent Paints
To simplify the specification process, and reduce the uncertainty surrounding paint for redecoration over existing paint coatings, we offer two fire protection systems that have been independently tested by the BRE: Flame Retardant Top Coats and Intumescent Upgrades.
We also offer a wide range of other high-performance and specialist decorative coatings, such as our Hygiene Defence system, Metal Defence system and Floor Protection system as well as a variety of primers, renders, external paints, and woodcare products.
All of our products are supported by our highly trained of technical experts. The team includes members who have worked in the industry, and they have first-hand knowledge of the challenges that specifiers and contractors face on a day-to-day basis. We are committed to providing advice and solutions that are technically led. Our suggestions are not swayed by cost - our primary objective is to ensure the right solutions are used, so that our customers and end-users have long-lasting decorative coatings that look good and contribute to fire safety.
Flame-Retardant Top Coats
The Flame Retardant Topcoats are to be applied as a minimum of two coats and are designed to inhibit the spread of flame. They are available in Durable Matt and Acrylic Eggshell finishes, with 16,000 colours to choose from. They are also low odour, quick drying and water based.
Both finishes are suitable for application onto new unpainted ceilings and broadwall surfaces, as well as for painting over sound existing coatings with up to 10 like-for-like paint layers.
The Intumescent Upgrade system is one of only a few complete solutions on the market today, which has been specifically formulated and fully tested to meet the highest fire-protective standards. It’s a four-coat system that can be used to upgrade substrates to the highest specification for surface spread of flame and propagation, providing that the existing substrate is suitable for redecoration. It is a water-based paint that is available in both Durable Matt and Acrylic Eggshell finishes, with 7,000 colour options.
Thank you for your time. We hope you found this CPD on the importance and specification of decorative fire protection for internal linings useful.
PPG Paint & Design Resources
Expertise and solutions for specifiers https://www.ppgpaints.com/architects-and-specifiers