The concern on Noman Qamar’s face is evident, when he starts speaking about the significance of raising awareness on issues looming around the testing and certification of fire-resisting ducts in the UAE. Qamar is General Manager, Central Ventilation Systems (CVS); Member, Board of Directors, AMCA International; and Member, Standard Technical Panel, UL555/UL555S.
He is concerned because of the potential risk factors the issues pose for the life and safety of the public. “Sometimes, when I interact with consultants, I notice that they tend to be more knowledgeable about certain products, namely air-side fans and energy efficiency solutions,” he says, looking wistful. “However, when it comes to products such as a simple duct, which is used for the transfer of air, they often do not give it much attention or in-depth consideration. It seems like they believe that there is no need for an in-depth understanding or focus, as the Civil Defence Regulations are in place, and manufacturers submit their Civil Defence approvals, accordingly”
The issue is not with the Civil Defence, though; it is with certain labs that seem to have found means to bypass the well-meaning stipulations laid down by the Civil Defence.
Qamar adds that the labs in questions get away with what they are doing because consultants may not be familiar with the specific product and its testing requirements, which is understandable, given their expertise lies in overall design and compliance with BS regulations. And hence, Qamar says, it is important for manufacturers like him to educate them on acceptable criteria.
So, what is the central issue we are talking about? Qamar explains: “Some testing labs have only conducted tests up to 400 degrees C and claimed compliance with BS 476/24 on the issued COCs, which is then used for Civil Defence approval by the manufacturers. A fire-resisting duct work, tested in full compliance with BS476/24, would be required to undergo fire tests following the ISO 834 curve, where the temperature in the furnace reaches up to 1,049 degrees C for two-hour-fire-resistance rating and up to 1,153 degrees C for four-hour-fire-resistance rating. Therefore, the duct tested with modified curve, maintained at 400 degrees C for two-hour or for four-hour, is not considered to be a fire-resisting duct under fully developed fire conditions. It is vital for everyone involved in the testing process to be aware of these requirements and conduct the tests accordingly.”
Weighing in, Quresh Motiwala, General Manager, Leminar Air Conditioning Industries, says that when it comes to fire-resisting ductwork, Leminar has always believed in driving awareness and providing opportunities to educate consultants and the authorities concerned on the latest standards through initiatives, such as technical presentations and seminars. “While some consultants have shown keen interest in discussing technical details and even get involved with manufacturers from the design stage, there is still a gap with some consultants who use old specifications and requirements,” Motiwala says. “Another challenge is that consultants may approve a manufacturer based solely on local Civil Defence approval without considering if the product is fit to meet the intended purpose. In some projects, manufacturers have received approval for low-pressure class duct construction for basement smoke extract with a lower galvanised sheet thicknesses than what is required for a typical FCU duct. However, it is important to note that there is no comparison between a normal GI duct for an FCU and a life-safety fire-re-sisting duct.”
Zainul Abedeen, Associate Consultant – Fire and Life Safety, WSP Middle East, who is also a contributor to the UAE Fire and Life Safety Code of Practice, says that while some consultants and fire engineers are knowledgeable about the testing and approval processes, in many cases the responsibility for approving materials falls on MEP engineers, who may not have the same level of expertise. “It is important for all consultants and companies involved in a project to understand the testing requirements and to ensure that all materials used meet the necessary standards,” Abedeen says. He also notes that different regions may have different approaches to testing and approval, such as the differences between European and American standards. “If there are different standards in different countries or regions, it may be important to consider the reasons behind these differences and evaluate whether they are based on sound scientific evidence and testing,” he says.
Abedeen says: “It is important for construction projects to prioritise fire safety by requesting specific features and complying with fire rating requirements, which can vary depending on factors such as building protection and chosen fire rating standard. Fire rating requirements can depend on factors such as whether the building is sprinkler-protected and which fire rating standard the designer chooses to follow. For example, the British BS standard requires consideration of stability, insulation, integrity and compliance with test standards and theory categories. In the construction industry, it is crucial to ensure that building materials and structures can withstand high temperatures and are fire-resistant. The British Standard 476 (BS 476) provides a code for fire tests on building materials and structures, including tests for stability, insulation and integrity.”
Abdullah Faza, Fire and Life Safety Division Manager – UAE, AESG, says that typically, these products are tested to maintain tenable egress conditions during fires by allowing safe egress of the occupants with controlled smoke accumulation. The HVAC ducts are required to be of the same fire rating as the fire compartment assembly the duct work is penetrating through, which is typically rated for one or two hours, he says. “The temperature profile also depends on the Smoke Plume Temperature calculation for atriums and similar vertical openings or large spaces,” he says. “However, the intention of testing a certain product for two hours is to ensure that the product is capable of handling minimum temperatures up to at least 400 degrees C and to ensure safe egress of the building occupants by maintaining tenable conditions. This may not be sufficient in all cases, especially if the building lacks automatic suppression systems, where fire control is absent. The optimum scenario is to study the highest expected temperature and record the required duct fire resistance accordingly. It is worth highlighting that some of the other international ducts fire testing standards require higher temperature.”
Qamar says that it is important to note that some of the stakeholders – consultants and contractors – even try to justify the use of 400 degrees C ducts, linking them with the fire rating of the smoke exhaust fans installed in the smoke management system. “The use of a fan operating at 400 degrees C for two hours as justification for this temperature parameter is questionable, as the installation location and testing conditions of ducts differ from those of fans,” Qamar says. “Therefore, it may be worthwhile to investigate and consider alternative testing methods. The importance of labs performing their duties with honesty and integrity cannot be overstated, and the consequences of non-compliance can threaten the safety and integrity of the industry. The GHQ has taken notice of this malpractice, and has taken necessary actions against the involved lab/manufacturers to enhance the integrity of the fire testing industry, as well as the safety of the built environment in the country.”
Elaborating on the issue of some labs testing for 400 degrees C and approving ducts as BS 476/24 compliant, Motiwala says that Leminar first noticed it with a few manufacturers testing their fire ducts at a temperature lower than 400 degrees C. “We visited the authorities and spoke to the laboratory to present the case and let them know why such practices were incorrect,” Motiwala says. “BS 476/24, a test standard for fire ducts, gives fire ratings to three criteria and constitutes a full-scale fire test where the temperature would typically reach 1,049 degrees C at two hours, as per the ISO 834 time-temperature curve. In a fully developing fire, as per the standard time-temperature curve, after two minutes from the start of a fire, the expected temperature reaches 444.5 degrees C, and at three minutes, this rises to a whopping 502.29 de-grees C. This demonstrates that any duct system that has only been tested to 400 degrees C cannot be used as a fire duct and would be expected to fail just after a fire starts.”
Motiwala says that according to BS 476/24, fire ducts must be tested for stability and integrity at full fire temperature to prevent collapse and maintain their cross-section. However, insulation testing depends on several factors, such as location, passing through compartments and proximity to other services, or flammable materials, he points out. MEP consultants may require insulation criteria of up to 400 degrees C for a smoke duct, depending on the risk and application, he says. “However, in my opinion,” he says, “the designer would need to study the project in detail, and this is where a manufacturer with profound experience like us could work with the designer right from an earlier stage of a project to give them an appropriate solution.” Abedeen shares a similar perspective and underlines that engineers must ensure that all three categories of testing are met, not just stability, which is rated for one hour, but also insulation and integrity, which are rated for shorter durations. He also says that it is crucial for MEP consultants in the region to be aware of the BS 476 code and its requirements for fire testing on building materials and structures. This awareness, he says, is necessary to ensure that buildings are safe and meet the required standards for fire resistance.
Discussing the consequences of using uniform time-temperature tests for ducts and smoke-ex-tract fans, Faza says that in ordinary commercial, residential or hotel buildings, the fire is not expected to grow rapidly, due to the absence of highly flammable or combustible materials or explosion-based fires. He also emphasises that time-temperature tests typically use t-squared fire growth models and are justified by empirical testing formulas.
Motiwala says that according to the UAE Fire and Life Safety Code of Practice, smoke extract fans must be rated at 400 degrees C for a period of two hours. However, the Code does not mention that the same requirement applies to fire-resisting ducts, he says. This is because smoke extract fans typically handle hot smoke and gases up to 400 degrees C inside the fans and exhaust them outside the building, while fire-resisting ducts run throughout the building and, in most of the cases, would be directly exposed to a fully developed fire, he points out. “In such a case, the fire duct must fulfill its intended purpose and meet the stability and integrity criteria at full fire temperatures,” he says. “It is important to note that applying the temperatures of smoke fan tests on fire ducts is not recommended, as it could cause system failures.”
Given the critical nature of the issue, it is baffling that any lab would choose not to wholly follow the expected procedures for testing. The cost of testing could be a factor. Abedeen says that as per his understanding, complying with the BS 476 standard is quite challenging, as it requires exposing materials to very high temperatures for extended periods, which can be costly and require specialised equipment. He notes that as a result, some labs may choose to test materials only at a standard temperature, such as 400 degrees Celsius, which may be more feasible in terms of cost and equipment requirements. However, it is important to note that the BS 476 standard specifies a minimum and maximum temperature for testing, with the maximum temperature being 1,100 degrees C. Labs must ensure that their equipment complies with these standards and are able to withstand the high temperatures required for testing. It is also important to prioritise safety over cost or convenience and ensure that materials are tested under conditions that are representative of real-life scenarios. Overall, it is a complex issue that requires careful consideration of various factors, including safety, cost, and compliance with regulations and standards.
The sheer risk of it all
The risks of installing ineffective fire-resisting ducts in real-life scenario need to be considered and taken very seriously, indeed. When speaking about the risks involved in using fire-resisting ducts that are incapable of performing their function, Qamar’s face is a mosaic of concern. Speaking of a particular hotel project, as an example, and the shortcuts that have been taken in terms of fire safety, Qamar says he would not feel at all comfortable staying there as a guest. “Pieces of information of these kinds led us to take the initiative to create awareness and spread the message,” he says. He also emphasises that the spread of awareness is crucial, as it could potentially save lives.
There are significant risks associated with fire-resisting ducts. If the duct is not properly installed, it could collapse or leak, allowing fire and smoke to spread to other areas, says Abedeen. “This could cause damage to property and potentially harm people’s health,” he says. “In addition to fire, smoke can cause damage to areas where there is no fire, and require cleaning and maintenance. Therefore, it is crucial to ensure that fire-resisting ducts meet safety standards and are properly installed to prevent these risks from occurring.” Contributing to the discussion, Motiwala explains about the two types of fire exposures: Type A (Fire Outside) and Type B (Fire Inside/Outside). Type A duct is designed to resist fire from the outside, such as ventilation make-up or pressurisation ducts. If it fails, it can prevent the pressurisation system from working, leading to smoke entering the exit passages and making evacuation difficult. A kitchen duct passing through compartments can also ignite if the insulation fails. Type B duct is built to resist fire from the inside, such as smoke extract systems. If it fails, the ducts cannot extract smoke from the building.
Faza points out that fire-resisting ducts are often equipped with fire dampers, which have a rating of one or two hours. These dampers are installed inside the ducts and are linked to a fusible link that closes the duct opening when the rated temperature is reached. Not having fire dampers in place can lead to smoke transfer between zones, putting occupants in non-fire zones at risk of smoke inhalation, he says. However, even if fire dampers are present, failure of the fire-resisting ducts, due to reasons other than the dampers, can still result in catastrophic fires, particularly if the ducts are meant for smoke control and the occupants’ ability to evacuate depends on their proper functioning. In such cases, the travel distance may not always comply with fire code requirements, he says.
The Civil Defence to the rescue
Qamar says he believes the Civil Defence is taking proactive measures to prevent fire-related incidents from happening. “However, it is concerning to hear that over 40 manufacturers have resorted to unethical practices in the last four years, which is why it is crucial to have robust legal systems to hold those responsible, accountable for their actions,” he says. “Although there has been a loophole in the system that enabled these practices to occur, the situation has been rectified. The Civil Defence had approved certain labs in the past and trusted their document approvals. It is vital that the Civil Defence establish a reliable and rigorous system to issue CoCs, to prevent any further incidents. It is also concerning that some contractors prioritise price over safety and quality, and it is crucial that all stakeholders in the construction industry prioritise safety and quality above price. Finally, while consultants may not always be aware of all the details, they must prioritise safety, and work within the legal system to ensure accountability.”
Motiwala says the authorities have taken steps to improve life safety by providing clear guidelines for testing and certification of products. However, all stakeholders involved in the project, including consultants, contractors and manufacturers, are responsible for fire safety. To ensure safety, manufacturers should be involved from the design stage to discuss suitable products for each project. “Fire ducts,” he says, “should be fabricated in the same factory as they were tested to ensure compliance with local Civil Defence approval. Regular factory visits should be conducted to ensure compliance. A ranking system for fire duct manufacturers, based on their manufacturing capabilities, credibility and reliability could be implemented to maintain product quality. Consultants and authorities should also gradually make new standards, such as EN 1366, a primary requirement, going forward.”
Faza says that the authorities have implemented many practical solutions, such as forcing the labs to follow only the approved standards for testing the fire-resisting ducts, and ensuring that all ducts, fans and smoke-extract equipment have been passed through a high-quality approval process that includes approved testing laboratory, approved certification bodies, approved suppliers and approved installers. “Moreover, the authorities having jurisdiction have published papers, standards and codes exposing the requirements of the design, installation and testing of ducts and equipment to make sure that all designers and installers have enough information to make sure that the system will function efficiently in real life in addition to the inspection by well-trained inspectors,” he says.
Abedeen says the UAE Fire and Life Safety Code of Practice is revised periodically to ensure it is up to date with the latest fire safety technology and best practices, and the revisions are based on feedback from industry experts, past incidents, and changes in regulations and standards. He adds that the Code covers fire safety aspects, including fire prevention, suppression, alarm systems, emergency response and evacuation procedures. The Dubai Civil Defence enforces the Code to ensure compliance for all buildings in Dubai.
Abedeen also highlights the importance of ongoing education and support for new consultants in the industry who are responsible for writing specifications for manufacturers.
Abedeen says manufacturers often prioritise cost-cutting over quality control, and hence, the role of testing labs and certification becomes crucial. Labs must test products against industry standards and certify them accordingly, he says. All stakeholders, including consultants, manufacturers and suppliers, should be aware of their responsibilities and take the initiative to constantly learn and improve, he says. He adds that a collaborative approach is vital to ensure quality control and adherence to industry standards in the construction industry.
“Consultants and manufacturers can start providing details for fire-resisting ducts on the project specification and Issued for Construction (IFC) drawings, which are submitted to relative Authorities for approval and review,” Abedeen says. “Currently, the testing requirements for such ducts are in place; however, implementation is the greater goal to achieve as an industry. Manufacturers can produce simple design documents that help designers to better understand their products in relation to how they will integrate into the passive fire protection design of the building, how it can meet the different expected temperatures for the variant occupancy types and what specifications shall be included in the IFC package.”