From massive facilities storing petrochemicals to the complex hydrocarbon processes conducted at oil and gas refineries, industrial sites must safeguard against threats posed by flammable materials and processes. Careful thought to the materials supporting passive fire protection can contribute to life safety strategies.

Beyond the immediate combustion risk posed by many flammable materials used in industrial processes, temperatures also present a concern. For example, temperatures quickly reach 2,000°F (1,093°C) in hydrocarbon-fueled fires.

Installed on industrial piping, equipment and structural steel, proper insulation systems can help defend against extreme temperatures and help support structural integrity in the event of a fire by obstructing the transfer of heat to the underlying surface. These insulation systems often rely on one or multiple layers of insulation materials that are non-combustible and will not spread flame or generate smoke. Examples of these may include cellular glass, mineral wool, ceramic fiber, calcium silicate boards, or endothermic mats. It is also possible to apply a hybrid approach combining insulation and Intumescent Fire-Resistive Material (IFRM) to protect the system. In such applications, an IFRM on the outside of the insulation undergoes a chemical reaction – expanding to form an insulating char - helping delay the movement of heat toward the piping, column, beam or other item that is being protected.

TESTING IN INDUSTRIAL SPACES & BUILDINGS

Where hydrocarbon fuels are present, the protection of piping and other construction needs to be protected differently than a typical building where only an ordinary combustible (cellulosic) might occur. The test standards, ASTM E119, Standard Test Methods for Fire Tests of Building Construction Materials or UL 263, Fire Tests of Building Construction Materials are used to evaluate the performance of walls and floors that form effective compartmentation – containing fire to the room of origin and maintaining the integrity of structural building elements and assemblies as well.

There are two test methods often used to evaluate the longevity of structural fire protection systems and assess the duration of protection provided by insulating materials in industrial settings where a hydrocarbon fire is possible. Evaluating passive fire protection systems in an industrial occupancy or space requires carefully considered fire testing methods, such as UL 1709 – Standard for Rapid Rise Fire Tests of Protection Material for Structural Steel - and the “jet fire” test or ISO 22899 – Determination of the resistance to jet fires of passive fire protection materials – part 1 – General requirements

Using the UL 1709 test method, protection materials can be installed on a material surface – for example structural steel – and placed in a 2,000°F (1,093°C) furnace environment. The temperature of the underlying substrate is then monitored with groups of thermocouples. The time at which the material being protected reaches an average temperature of 1,000°F (537.7°C) across a thermocouple group or any individual thermocouple reaches 1,200°F (649°C), the test is concluded and a protection time rating is given to the insulating material or system.

The jet fire test – ISO 22899 – is also used to evaluate materials. This test assesses how an insulating material responds to direct flame impingement or localized fire events. The insulating system is sprayed with fire coming from a designated spot – similar to a stream of fire from a hose nozzle.

To assess the performance of passive life safety systems, Owens Corning collaborates with testing organizations such as UL to investigate how multiple passive fire systems perform in industrial settings. In 2021, Owens Corning conducted both UL 1709 and ISO 22899 tests to collect data and validate material performance. The results from these tests offer three insights for designers and installers of passive fire protection systems used in industrial environments:

INSIGHT #1: INSULATION OFFERS DUAL BENEFITS

Beyond providing thermal resistance, proper insulation can offer passive fire protection in industrial settings beyond operating temperatures of processes. Properly specified and installed insulation systems deliver up to several hours of protection against fire. Insulating systems can guard against extreme temperatures, manage thermal flux, and extend the time for protected elements to reach dangerous temperatures where structural strength can be lost.

Like all facilities, life safety in the industrial space will always be a top priority. As passive fire protection systems work to support structural integrity in the event of a fire, such systems provide time for a fire to be brought under control and equipment and processes to be safely shut down. Testing has demonstrated the ability of insulating materials to help safeguard against rapid temperature rise of a structural element in a hydrocarbon-based fire. Properly specified and installed, a passive insulating system may deliver several hours of mitigation during a hydrocarbon fire. Similarly, jet fire testing shows that insulation-based passive fire protection systems can supply more than an hour of protection for the insulated substrate in jet fire scenarios.

INSIGHT #2: MATERIAL PERFORMANCE AND ENVIRONMENTAL APPLICATION MATTER

In passive systems, the properties of a thermal insulation as well as the environment – below-ambient, ambient, or above-ambient temperatures –influence performance. Installed in systems protecting structural steel, equipment, piping and hydrocarbon storage tanks or spheres, both the composition of the material and temperature range matter. When evaluating a material, specifiers should consider whether it is combustible, spreads flame, or generates smoke. Suitable materials will not support combustion, spread flames or develop smoke when exposed to fire. However, it should be noted that some ancillary organic system components such as sealants, vapor barriers, or coatings may support limited combustion or smoking to take place. Specifiers should also consider how the mass, thermal conductivity and service temperature range (during operations) of the material could influence performance in the event of a fire. Additionally, for applications where absorption of flammable process liquids is a concern, non-absorbent insulations should be considered. Note that just because a material is non-absorbent or hydrophobic to water, it does not mean that it will not absorb non-polar molecules such as flammable fuels.

With these qualities in mind, examples of suitable materials for passive fire protection may include cellular glass, mineral wool, ceramic fiber, calcium silicate boards, or endothermic mats. From here, one can further narrow down suitable materials based on the environmental application. As an example, cellular glass insulation systems can be designed to perform across a wide service temperature range from cryogenic to hot applications, while mineral wool systems are generally designed to perform on above ambient to high temperature systems.1 In any case, it is important to ensure that both fire resistance and thermal insulation needs are being considered when selecting an appropriate material for passive fire protection systems.

INSIGHT #3: MATERIAL CAN SUPPORT BOTH TIME FOR EVACUATION AND THERMAL PROTECTION

Both the operating environment and the processes/ application should inform material and fire property specifications. In many situations, specifying a multiinsulation material system can optimize the level of protection while supporting ancillary benefits such as noise reduction. Jet fire testing has shown that combining cellular glass insulation with mineral wool or with an Intumescent Fire-Resistive Material can deliver up to four hours of protection. Regardless of type, all insulation systems used to fire protect these assemblies need to pass fire tests proving the protection lasts as claimed by the manufacturer. The results of tests can be found at online directories such as UL’s Product iQ.

CONCLUSION

Passive fire protection systems can help address the enduring threat posed by materials and processes in the industrial sector. Properly designed and installed insulation systems can help safeguard occupants as well as structural building elements, equipment and piping that drive processes in manufacturing operations. Testing aimed at determining how long passive fire protection systems function under conditions of rapidly increasing temperature or focused-fire situations can be used to identify three key insights to support passive fire protection decisions. First, thermal insulation can also provide passive fire protection. Second, the materials in these systems matter. And third, a combination of insulating materials tailored to the environment and application can improve the performance of these materials. Careful thought to materials – and the listings resulting from correct fire tests for the environment expected - can contribute to a high-performing passive fire protection system

Service temperature limits are derived from laboratory evaluation of the product. Variations in substrates, loading conditions, or other external factors may further limit service temperature.

Author: Tim Bovard, Manager, Technical Services and Training at Owens Corning Alec Cusick, Technical Service Engineer at Owens Corning

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Source: Life Safety Digest