26 Dec A fire and life safety assurance
With the rapid advancement in technology in constructional techniques and the development of new materials, architects have identified an opportunity to harness those techniques and materials to design innovative high-rise constructions, with eye-catching façades, which have created striking new landmarks. However with these new advancements come additional risks, and an understanding of the façade regulations in the UAE is vital, explains David Campbell, Divisional Director, Fire & Building Products ME & India, Al Futtaim Element Materials Technology and Fawaz Hashim, Senior Engineer, Fire & Building Products, Al Futtaim Element Materials Technology.
To address these risks, various countries, including the United Arab Emirates (UAE), have developed their own particular test regime. In these tests, an attempt is made to recreate the cladding in a way that could represent a façade as it may be built in standard practice. During the tests, the mechanism of the spread of fire over the cladding is monitored. The recorded data can then be compared to the recorded performance of the system with relevant fire safety requirements to determine if the proposed system is acceptable or not.
UAE fire code
In the UAE, all materials that are intended to be used on exterior façades must be tested and listed, based on the requirements stated in the UAE Fire and Life Safety Code of Practice (UAE fire code), October 2018. Natural stones and concrete are not required to be tested. The UAE fire code has been subjected to address an extensive amendment to the previous edition on the various evaluation processes of the new advanced products that are now available on the market.
With the thorough investigation and examination of past regional and international incidents involving façades and cladding fires, certain construction materials and products have been prohibited for use in a façade system. One product not allowed is any insulation that does not achieve a Class A when tested to ASTM E84 or UL 723.
To ensure that a project does not miss out on evaluating the property of the façade system as a whole, the UAE Civil Defence (CD) has implemented a 10 point approach scheme to ensure the product/system they are approving would be safe on a building. The following are the ten check points the authority has listed.
The core of the façade material shall be tested in exposed form as per test requirements of the UAE Fire and Life Safety Code of Practice (UAE fire code), October 2018.
Façade panel as a product shall be tested as per test requirements of the UAE fire code.
Façade system as wall assembly shall be tested or listed as per test requirements of the UAE fire code.
Curtainwall, perimeter joints and fire stopping shall be a listed system with a recognised certification body (CB).
Cavity fire barrier bands shall be provided in concealed cavities between façade and primary substrate, at every slab termination.
Fire breaks shall be provided vertically between where internal walls terminate against the back of the exterior façade system.
Exterior sprinklers should be considered for the balconies, and interior window sprinklers should be considered for the glazing of buildings.
Recognised consultants must have competent and qualified façade specialists in-house, or they must engage a CD approved house of expertise who has experience and knowledge in façade consultancy for façade design, system selection and supervision of the façade contractor.
Façade contractor and fabricator must be approved by CD, with a valid CD License.
Façade installation must be inspected throughout the installation process and certified by the recognised consultant or CD approved house of expertise.
The testing regime outlined in the UAE fire code, provides a well-defined procedure to be followed for a product or a system approval.
Reaction to fire testing
There is also some resistance to fire tests identified in instances where the external wall of a building, that will have a cladding system attached to the base wall, is required to prove certain fire resistance performance characteristics. This is usually where there is separation from the boundary considerations, proximity to other buildings and external egress stairs, etc. Note that it is not the cladding system that is achieving the fire resistance in the tests, it is the base wall which is usually constructed of non-combustible material such as concrete blocks. Resistance to fire test methods do not prove the performance characteristics of the propagation of flames across or up a building façade system.
For the individual components of a façade system, the UAE fire code identifies a choice of various reaction to fire test and classification methods, norms and standards that include classification to EN 13501-1, testing to ASTM D1929, NFPA 268, ASTM E84, UL 723 and BS 476 Part 7 as part of the requirement in the approval process. Among these standards, EN 13501-1 has several classifications for which there are other test methods to evaluate the performance of the product for different parameters based on the classification required.
In the current UAE fire code, for super high-rise and high-rise buildings, all products must meet the requirements of EN 13501-1 Class A1 or A2-s1,d0 and mid-rise to low-rise buildings B-s1,d0. In addition to this classification, certain products that have combustible materials with the composition or the presence of plastics must undergo an additional evaluation in accordance to ASTM D1929 or NFPA 268.
A brief look at the classification scheme in accordance with EN 13501-1
Certification
A façade assembly cannot be evaluated for its performance in a fire scenario by having test evidence alone for its individual components. The design of the overall façade build-up plays an important role in the overall performance of the assembly. To validate this, there are assembly tests listed in the UAE fire code. One of the UAE fire code’s longest identified acceptable methods for fire performance of the façade assembly is the NFPA 285 test. In the 2018 update of the UAE fire code, British Standards test BS 8414 Part 1 and Part 2 were added to the recognised façade assembly test list, with evaluation as per BR 135. Both BS 8414 and NFPA 285 are today the acceptable standards throughout the greater Middle East and India region to evaluate the fire performance of a façade assembly. In addition to these, to ensure a wider market can achieve UAE product approval, standards such as FM 4881 and ISO 13785-2 have more recently been included
as acceptable.
The UAE, similar to other countries, has a pathway to approval for products and façade systems. The factory or the manufacturing facility is initially visited and audited by an approved CB for its Quality Management System (QMS) and factory production control. Product samples are witnessed, marked and sent for testing and evaluation by a recognised and accredited testing laboratory. Any improvement actions noted during the audit must be adopted, actioned and closed out prior to the certification being granted. A successful test and audit of the factory would entitle the products and façade system to be issued a certificate by the CB.
In the UAE, unlike other countries, there is an additional step in the approval process. This is the submission of a UAE CD Certificate of Compliance (CoC). This is on a UAE CD Ministry of Interior letter head template document that is prepared and populated by a UAE CD recognised CB, compiling the various test results, test report references and the correlating product/system certification certificate.
The CB takes the liability of ensuring all aspects of the product/system are evaluated prior to issuing the CoC for the product/system. They must ensure the compliance of the product/system to the tested standards, the technical requirements of the CB and most importantly its compliance to the UAE Fire and Life Safety Code of Practice (UAE FLSC), Oct 2018. The CoC is then uploaded as part of a product or system approval process by the manufacturer or their legal representative / agent on the UAE CD portal for approval. The approving authority then reviews and validates the test data, the certificate and UAE CD CoC for compliance once again prior to processing the approval.
The UAE fire code recognises the current situation where there are a growing number of architectural advancements in the Middle East region. Building envelopes are likely to have unique shapes and designs. In many instances, these designs are without a clear distinction between façade and roofing and quite often you can find a single envelope is detailed to be installed as continuous roofing and façade envelope. CD with these types of design respond with a requirement based on the proposal reviews of the materials and system to assure both the façade and roofing satisfy the test requirements and are additionally subjected to “mock-up” tests.
In other situations, due to supply and demand considerations, where a contractor would need to replace any component of the system with an alternative but similar component, this is considered a design deviation to the approved tested and certified listed assembly system. In such a scenario, permission must be sought from the CD to proceed with the replacement component by providing an engineering evaluation, (locally referred to as engineering judgement [EJ]) as evidence. As such, if the CD gives its permission to proceed, an EJ shall be evaluated and prepared by the CB. The EJ is site specific to that actual façade assembly on that project, considering all deviations from the original approved system. The CB submits the EJ to the project through the manufacturer and it is reviewed and stamped jointly by the main consultant, house of expertise, cladding contractor, façade system manufacturers and façade installers. This EJ should serve the purpose of proving the compliance of the replacement material or deviation to the one that was tested and listed. Where there is insufficient actual test data and known science to support the CB in making the technical decision for issuing the EJ, then additional reaction to fire tests of materials and even the façade system may need to be undertaken.
The last part of the UAE CD acceptance of the cladding system is the inspection of the installation during construction. The inspection is undertaken by UAE CD recognised consultants or house of expertise with personnel having technical expertise in façade systems. Inspections are carried out at 20%, 40%, 60%, 80% and 100% stages of the installation. The inspection evidence is compiled and submitted to the project as part of the project completion and final inspection by the responsible CD.
To conclude, the fire and life safety assurance programme, as we can collectively term it, in the UAE is a combination of verifying the product/system compliance at different stages throughout the manufacturing, design and installation. They are monitored for their compliance with the standards through various third party certifications and eventually, before being installed on a building, they are verified by the consultant for its compliance to the local UAE fire code.