Use fire retardant paint when you need to slow the spread of fire, and use fire resistant paint when you need to protect the structural integrity of your asset.
DEMONSTRATION OF INNOVATIVE FIRE PROTECTION COATINGS FOR STEEL STRUCTURES
Executive Summary:
FP7-SME-2008-2-STEELPROST Research Programme Project outcomes provided a solution to current surface treatment limitations by developing a second generation fire-protective coatings solution comprising:
• An enhanced intumescent formulation.
• Efficient spraying and drying systems.
• Detailed study of the application of developed solutions according to the EuroCodes and CE Legislation.
SteelProst was a 30 months FP7 Research for Associations project under Grant Agreement number: 243574-2. Overall budget sums up 2.387.000 €. Steelprost Consortium represented Structural Steel stakeholders. Three European Associations; SGG (Slovenian Construction Cluster), AIN ( Asociación Industrial de Navarra) and ECCS (European Convention for Constructional Steelwork ) are the driving force of a consortium that also includes ALCEA (paint manufacturer, Italy) and Bersch und Fratscher ( spray gun manufacturer, Germany) as supply chain SME´s. Talleres Ruiz (Spain) and RAZPON (Slovenia) participate as end users and technology validators.
In order to continue with the exploitation and route to market, SteelProst Consortium Associations and Industrial Partners applied for a demo project that has been funded by the European Comission: STEELPROST – DEMONSTRATION OF INNOVATIVE FIRE PROTECTION COATINGS FOR STEEL STRUCTURES (FP-SME-2013, Grant Agreement 604920)
Project Context and Objectives:
The objective of the project was to validate and certify the previous SteelProst project results in order to transform research results into available commercial products. At the end of the project, important knowledge and technology advances have been achieved on the different tasks addressed:
• ALCEA has scaled up the production of the new intumescent coatings and has tested the material according to EN-13381-8 normative. Carried out tests will offer classical tabulated data and the λ variable values.
• Dürr Systems Karlstein GmbH and AIN have developed an automatic spraying and drying prototype that significantly reduces processing times and costs with an optimal applied thickness control. Tailor-made plants are available for steel constructors under request.
• CMM, member of ECCS, and SGG have made the assessment of FR according CE legislation and the EuroCodes. Detailed guidelines on procedures and calculations for cost efficient fire protection of structural steel are available allowing steel constructors to efficiently protect steelworks against fire and address new scenarios in which steel was not currently competitive.
• Talleres Ruiz, project coordinator and structural steel designer and manufacturer has integrated all these processes and results into its CE marking offering cost efficient and dully supported fire resistant structures.
At the end of the SteelProst DEMO (12-2015) project the integrated solution is available for the Structural Steel European Industry increasing their competitiveness; it is expected to gradually recover the 50% market share lost by the steel construction market during the last 10 years. Around 10% should be recovered in the first five to ten years of commercialization
Project Results:
Since the beginning of the project, September 2014, the Consortium has developed an integrated solution that combines a nano-enhanced intumescent coating, automatic spraying and drying techniques and advanced engineering criteria. All these concepts have been integrated in the CE marking of Steel Structures manufacturing process.
The new intumescent coating has been tested in order to obtain the necessary inputs to address currently non-addressed fire scenarios in which intumescent coatings are particularly efficient. Section factors ranges and FR values currently out of the performance of State of Art Intumescent Coatings have been covered.
As examples of cases in which FR values of 90 and 120 minutes can be achieved with thin intumescent layers; open parks, residential building, hospitals, hotels and others.
In order to efficiently coat structural elements, work done in automatic spraying and drying allows to coat a beam with a 1000 μ dry intumescent coating in less than 10 minutes. Each spraying and drying device is equivalent to five teams of painters working on site and cost reduction is the range over 75% of total spraying costs.
The whole solution has been integrated into CE marking procedures including the different case scenarios definitions, FR requirements and quality control procedures for the overall steel manufacturing and fire protection. Time and cost savings have been evaluated and the implementation of the new solution allows steel to be competitive in traditionally concrete controlled sectors like residential buildings and others.
In order to allow the efficient use of the new developed technologies, most representative scenarios for real Steel Construction have been evaluated in detail; residential buildings, warehouses and open parks. The translation of complex structures into simple elements to allow the use of simplified methods has been accomplished and detailed on a guideline. To provide efficient tools based on Excel and also ELE-FIR software have been generated. Currently the Consortium is working in an agreement with Engineering Software companies to integrate SteelProst advances in engineering software.
The technology has been protected through a European Patent and the next Exploitation stages include agreements with key intumescent coatings manufacturers for project European and non-European project deployment during the next years.
Potential Impact:
SteelProst Demo exploitation is expected to allow steel construction to recover a 50 percent of market share lost during the last years 10 years in the next five to ten years. The exploitation of the project will not only allow steel manufacturers be more competitive versus other construction technologies like concrete. Moreover an important opportunity has been generated in some markets like open parks, residential buildings and others in which the steel industry is trying to assume a market share.
The SteelProst Project deployment it is expected to impact and change currently implemented FR assessment and protection of steel structures based on inaccurate estimations that results into risks, inefficiencies and over costs. The new structural steel FR approach based on advanced engineering, translated to simplified methods and integrated in the EuroCodes and CE marking provides:
– Cost efficient fire protection.
– Security and dully validated FR values to address administration requirements.
The implementation of automated spraying and drying processes will not only reduce costs and times but also will allow to deliver intumescent paint coated steel elements under stringent quality control procedures. Developed solution can be assimilated by SME´s resulting into affordable Return of Investment values.
Fire Resistant vs. Fire Retardant Paints
When picking the right paint for your asset, it is important to note the key differences between fire-resistant and fire retardant coatings.
Fire-resistant paints work by creating a barrier against flames. Most of these coatings are intumescent paints, which work by forming a char layer on the substrate when met with flames. These paints are often applied to steel, timber, and plasters to avoid burning and destruction. This paint works by creating gas bubbles that strengthen the paint’s additives when met with flames. When used on steel and timber, the foaming char layer works to add time before flames can penetrate through the substance.
Fire-resistant paints are usually ASTM E-119 tested and certified. ASTM E-119 measures the the time it takes for a coating to fail under extreme heat and flame. Usually these fire ratings can last anywhere from 30 minutes up to 2 hours.
In contrast, most fire retardant paints are not ASTM E-119 tested or compliant. They prevent flame spread and typically have an ASTM E-84 rating. If a building material catches fire, the fire retardant paint works to slow the rate that the flames spread.
However, these paints and coatings are typically not appropriate for critical infrastructure like steel. For most projects that involve structural steel or other critical infrastructure, you’ll need an ASTM E-119-certified fire resistant paint.
FlameOFF’s Fire Barrier Paint provides an eco-friendly fire resistant coating that’s 100% ASTM E-119 and E-84 compliant.
Key features include:
- E-84 compliant: Class A flame spread (tested and certified by a 3rd party lab)
- ASTM E-119 compliant: 1 and 2-hour fire rated for long-lasting protection
- Compatible with steel, wood, gypsum, sheetrock, metal, and more
- Eco-friendly, low VOC, water-based intumescent coating
- Gold Supplier Member of National Fireproofing Contractors Association
Types of Fireproof Paint
Now that we’ve covered “fireproof paint” or, rather, fire resistant paint, it’s time to talk about the types of coatings most commonly used for fireproofing.
Two of the most important types of fire resistant paint are intumescent and cementitious paint formats. Cementitious coatings are an older fireproofing that creates a thicker barrier with a cement-based mixture and a binder that adheres to the substrate. Cement is naturally fire resistant, so the cement essentially augments the paint with fire resistant properties.
Cementitious coatings began surfacing in the mid-1900s when durable fireproofing solutions were needed. Concrete enhances the fire strength of a steel building, thus making cementitious paints an option. Over time, as dense concrete became too bulky, lighter cement paint methods were created. This type of coating is best in areas with low moisture exposure, as high moisture can cause an excess of corrosion and can reduce the effectiveness. Two of the biggest benefits of this coating are its affordability, especially for larger projects as well as its lightweight format.
Intumescent paint is a newer method and works by growing and forming a barrier when exposed to extreme heat.
Intumescent paints are relatively newer to the market but show excellent fire ratings and durability. Rather than being mixed with concrete to provide resistance, these coatings expand and char when introduced to flames. Intumescent coatings have been known to swell up to 25 times their original thickness when exposed to fire! The expansion of this coating is vital, as it allows for the volume to increase and the density to decrease, which in turn slows down the heating process. Intumescent paints are easier to apply, have reduced labor costs, and do not allow for gaps, making them better for moist environments. However, this paint is highly sensitive to changes during curing time and can be a costlier choice if multiple coats are needed.
While both formulas have their benefits and disadvantages, the general fireproofing industry often recommends intumescent paint for the majority of common applications. Cementitious paints are not the best for aesthetic appeal and can add weight, while intumescent paints blend into the visuals of the project.
The table below can help you determine which type of fireproofing is right for your project.
| Cementitious Coatings | Intumescent Paints |
| More cost effective | More expensive |
| Not intended for visible areas of a building | Aesthetically pleasing |
| Coating can crack | Smoother finish |
| Heavy concrete | Lightweight formulation |
Understanding Fire Rating Standards
Before selecting the paint for your project, it is important to pay close attention to the fire rating standards needed in your specific project. While there are a variety of standards, certain standards must be met for different styles of application. Here is a look at some of the most common ratings and their meanings:
- ATSM E-84/UL 723- usually just called the “E-84”, this is the most common fire standard. This test measures the flame spread along a sample to determine the predicted burning behaviors. When working on new projects or renovations, keep in mind that almost all facilities require an ASTM E-84 test.
- UL 263– This method rating tests and certifies the fire protection of structural steel. Often called the “default standard for North America,” this method is key to testing the structural steelwork fire protection before a project is finished.
- ASTM E-119– This rating/test evaluated the fire-response to a variety of structural substrates in a project. This rating is used specifically to test load bearing items such as walls, partitions, columns, floors, roofs, and structural beams.
- ASTM E-2768– A newer standard in fire ratings, this test is usually called a 30-minute version of the ASTM E84 test. This test is used for more intricate estimates of fire protection.
- NFPA 703– This test works best when used on fire-retardant-treated wood building materials.
- NFPA 286/UL 1715- These tests are often the go-to “defacto room corner tests” and are best for interior testing. The general test room is an 8 foot by 12-foot room with open or closed cell spray foam.
In addition to these tests, paints also come with fire retardant classifications of A through C. The system was originally developed by the National Fire Protection Administration for their “Line Safety Code”. When observing the rules of buildings, make sure to take into account the required retardant classification before purchasing your paint materials.
[top] Steelwork fire resistance
Large, heavy sections heat up more slowly than smaller, lighter sections and so have more inherent fire resistance
All structural steel sections have some inherent fire resistance and this is a function of the size of the section, its degree of exposure to the fire and the load that it carries.
The fire resistance of an element is usually defined as the time for which the element can satisfy appropriate criteria (for example, its load-carrying resistance). Tests are undertaken in a furnace where the temperature follows a standard time-temperature relationship as shown, which is the same for all materials. The standard time-temperature curve does not follow the general behaviour in a real fire, where the temperature falls once the fire load (matter which burns) has been consumed. The fire resistance periods obtained in a test are a measure of the adequacy of the construction in a fire but have no direct relationship with the duration of a real fire. BS 476-20 [8] , ISO 834 [9] and BS EN 1363-1 [10] describe the standard test.
The strength of structural steel decreases with temperature. Following an extensive series of standard fire tests, that strength reduction has been quantified. Recent international research has also shown that the limiting (failure) temperature of a structural steel member is not fixed but varies according to two factors, the temperature profile through the cross section and the design load.
For small, fully loaded sections, exposed on all four sides, the inherent fire resistance without added protection can be as little as 12 minutes. For very large sections, lightly loaded and with some partial protection from concrete floor slabs on the upper flange, this can be as high as 50 minutes. Where the heated perimeter is further reduced by the method of the construction (e.g. shallow floor systems), up to 60 minutes inherent fire resistance can be achieved. SCI-P186 describes methods of designing steel framed buildings for 30 and 60 minutes fire resistance without applied fire protection.
The standard fire test time-temperature relationship
The decrease in strength of hot rolled structural steel with temperature
Where the inherent fire resistance of the steel is less than that necessary to meet the requirements for structural stability for the building, additional precautions must be taken. This usually takes the form of applied fire protection which insulates the steel from the increasing temperatures. The fire resistance of hollow sections may be increased by concrete filling, which may mean that external fire protection is not required.
[top] Design using structural fire standards
The world’s first design code for steel in fire, BS 5950 Part 8 [1] was published in the UK in 1990 and redrafted in 2003. It is based on extensive testing by Tata Steel and the Building Research Establishment (BRE) and brings together in one document details of many of the methods of achieving fire resistance for structural steelwork. Although it is based on evaluation of performance of structural steel members in the standard fire test, it may also be used in fire engineering assessments when parametric fire temperatures are derived by calculation.
BS5950 Part 8 [1] also includes design information and guidance for design of portal frames, hollow sections in fire, external steelwork, composite slabs and calculation of fire protection thicknesses based on limiting (failure) temperatures. Background to the standard and worked examples (to the 1990 version) are given in SCI P080.
The following Eurocodes describe the rules for the fire design of buildings using structural steelwork:
- BS EN 1991-1-2 [11] ,
- BS EN 1993-1-2 [2]
- BS EN 1994-1-2 [12] .
The fire Eurocodes are more comprehensive than BS5950 Part 8 [1] . A greater level of detail is available on material properties and, as well as dealing with most of the subjects covered in BS5950 Part 8 [1] , the combined suite of fire Eurocodes also introduces the concept of time-temperature relationships for different types of fire, including parametric fires. These are fires which are specific to the conditions in the building being considered. Three levels of calculation are provided: tabular; simple and advanced.
The tabular methods are used for direct design when certain parameters relating to loading, geometry and reinforcement are known. Simple methods are generally considered to be suitable for hand calculation, although they are often quite complex (generally much more so than in BS5950 Part 8 [1] ) and may often require the development of spreadsheets or bespoke programs. Advanced calculation models are only appropriate for computer analysis and not for general design. Free design software is available for the design of both beams and columns at elevated temperature.
Design Eurocodes are accompanied by National Annexes which provide instruction on values for certain nationally determined parameters and also on elements of the standards which are not applicable in the UK. This recognises the responsibility of the regulatory authorities in each member state to define their own required levels of safety. The National Annex may also contain guidance on the application of informative annexes in the Eurocodes and references to non-contradictory complementary information (NCCI) to assist the user to apply the design rules in the Eurocodes.
Comprehensive advice on the fire resistance of steel framed buildings in accordance with the Eurocodes is given in SCI P375, and worked examples following the simplified calculation models, covering the verifications of beams and columns are presented in SCI-P403 and available here.
[top] Fire protecting structural steelwork
Passive fire protection materials insulate steel structures from the effects of the high temperatures that may be generated in fire. They can be divided into two types, non-reactive, of which the most common types are boards and sprays and reactive, of which thin film intumescent coatings are the best example. Thin film intumescent coatings in turn can be either on-site or (more commonly) off-site applied. The UK has an efficient and competitive structural fire protection industry which can deliver cost-effective solutions.
Thin film intumescent coatings are paint-like substances which are inert at low temperatures but which provide insulation by swelling to provide a charred layer of low conductivity material when heated. This char is an excellent insulator. Thin film intumescent coatings dominate the passive structural fire protection market in the UK.
Thin film intumescent coatings can be specified with an aesthetic or a non-aesthetic finish. The cost differential can be considerable and care should be exercised to ensure that the specification is consistent with the visual requirement.
Boards are also a popular type of fire protection in the UK. They are widely used both where the protection system is in full view and an aesthetic appearance is required, and where it is hidden. Boards can be divided into two families. Those which are suitable for the application of decorative finishes are generally quite heavy, and more expensive, than the non-aesthetic, lighter materials.
Sprays protection systems have decreased in popularity, despite being one of the cheapest forms of fire protection in terms of application costs. This is mainly due to problems with overspray and impacts on the construction program.
Flexible, or blanket, fire protection systems have been developed and fill a niche where complex shapes such as truss members require protecting but where a dry trade is preferred.
Concrete encasement can also be used as fire protection for structural steelwork. This method has only a small percentage of the fire protection market in the UK. Blockwork filling between column flanges may be used to increase fire resistance.
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Fire protection systems
Board protection showing a heavy, aesthetic product on the column and a lightweight, non-aesthetic system on the beam
(Image courtesy of Promat Ltd.)
Aesthetic thin film intumescent coating.
(Image courtesy of Sherwin-Williams Protective and Marine Coatings)
