Fire behavior report, comments and discussion concerning Dubai Municipality circular no.215

​

Abstract:

​

This report addresses two main issues as following:

​

1. The fire behavior and compliance of ETFE materials to recognized international standard.

 

2. Conclusion of report reference to Dubai Municipality circular no. 215 concerning fire protections. Dubai Municipality circular 215 is advising designers that ‘’ All hard roofs building envelopes facades, doors and windows have to be NON-COMBUSTIBLE with fire resistance X-hours ‘’ which is causing big confusion or mix up when fabric, membrane or foils(ETFE) are being used as elevated skylights and facades. The ETFE accordingly is being confused with hard materials facades/roofs non-combustibility x-hours and accordingly some consultants and firms-unfortunately- thinks that ETFE shall not be used confusing it with hard materials envelop which is flagrant wrong understanding to Dubai Municipality & Civil Defense regulations and the ETFE super safe fire behavior.

 

 

​

 

1. The fire behavior and compliance of ETFE materials to recognized international standard.

 

 

ETFE Foil as material (with a melting point of approx. 280° C) is classified as a low flammable material and is considered as self-extinguishing. In the event of a fire, the heat of smoke will cause the foil to soften and shrink away from the fire source and create a natural ventilation. In some cases, the smoke at the ETFE-surface won’t reach a temperature, which will cause the ETFE-foil cushion to melt, therefore, it is worth considering the installation of automatic actuators in facades or roofing-areas in order to ventilate the space of smoke if proved required by fire engineer. The quantity/weight of the ETFE-material (~440 g/m² for a foil thickness of 250 µm) used in a roof or in a façade is insignificant regarding to its fire load.

ETFE foil has passed many international standards and is classified as follows:

• DIN 4102                                          Class B1

• EN 13501-1                                      Class B-s1,d0

• NFP 92-505                                      M2

• NFPA 701                                          Pass

• UL94                                                  V-0 

• UL 723 / (ASTM E84)                        Pass/Class A

• JIS A 1322                                         Class 1

• JIS K 7201-2 (ISO 4590-2)              Limited Oxygen Index 29.1% (nonflammable in air)

 

It is understood that in almost all countries the elements of the building envelope has to have fire resistance duration X-hours and a sufficient resistance to swirling sparks and radiant heat. These requirements all of the thin membrane materials, including ETFE foil,  does not meet and therefore, the fire protection experts, who are experienced in building with membranes, follow a different philosophy due to building envelopes, especially made of ETFE foil, with respect to the fire protection plan. This philosophy can be described as follows:

 

ETFE-foil need not to have any fire resistance duration, because the ETFE melts at a certain temperature, opens and works as a natural smoke vent. No burning droplets occur, no impermissible smoke develops and it is self-extinguishing when the flame goes out or the fire is far enough away from the ETFE-foil (also called ETFE-film). Consequently, the fire behavior of ETFE-foil, applied in a roof or in a façade area, can be described as very safe, referring to the flame spread and fire propagation.

 

The realization of ETFE foil used for roofs, facades and building envelopes for large grandstands, domes, stadiums or arenas, as well as shopping centers or botanical gardens, with thousands of visitors each year, would otherwise be unthinkable. The large ETFE foil surfaces of the Allianz Arena and the AWD Arena in Germany, the Olympic Stadium in Beijing and shopping malls in England (e.g. Canary Wharf at Crossrail Station in London) and in France (e.g. Lyon Confluence) show, that this philosophy of the fire experts has been proven as safe.

For all the buildings that are serving to a place of assembly, normally two fire experts are involved, beginning their work in the early phases of the project:

 

The first one is a fire expert for buildings, who develops a project-specific fire protection and rescue plan. This plan considers all conditions and circumstances of the building, its utilization, rescue measures but also the fire behavior of the used building elements, as example a roof or a façade made of ETFE-foils or ETFE-foil-cushions.

 

The second expert is also a fire expert, but specialized on the evaluation and assessment of the fire behavior of building elements and material components. This expert preferably comes from the institute with the accredited fire test laboratory. He evaluates the certified material classifications, but also the test results of additional small material fire tests (if necessary) and, finally, he evaluates the mandatory large fire tests, carried out on a realistic 1:1 section of the planned façade- or roof area – normally with flame treatments from above (lying signal rocket), from beside (façade area) and from below (roof area). All tests are done according to the relevant standards. This expert report includes recommendations, to be provided to the above-mentioned first fire expert for his consideration in his project-specific fire protection and rescue plan.

 

This philosophy has been applied successfully many times in many countries. The resume is, that the application of ETFE-foil as building envelope material in roof- and façade areas is possible and safe, even the foil doesn’t comply with the requested standard of a so called “hard roof”.

​

​

2. CONCLUSIONS WHY ETEF DOES COMPLY WITH DUBAI MUNICIPALITY AND CIVIL DEFENSE REGULATIONS

​

• The concept of circular no.215 is to minimize the risk of fire and safe guard souls and properties. From aforementioned report, the fire behavior of ETFE material is safe and compliant with wide range of international recognized fire behavior codes and undergone independent third party classification class 0 to BS and B S1 d0 to EN.

 

•  Circular 215 does not apply on ETFE as the circular focused on facades or elevations which are starting from walk-able/habitable/usable ground levels(less than 2.0m from pedestrians) and extending further(in other words main building envelop), like example the circular has mentioned distances limitation between windows and doors and has distinguished two kinds of fire retardants for villas and other commercial elevations/facades.However, ETFE applications in elevated skylights or facades are always far from usable ground levels(greater than 2.0m from pedestrians). We believe this circular would be strongly applicable if ETFE was forming a main building facade/envelop starting from pedestrian ground level and from each usable level or in case ETFE was part of covering any main building facade or materials made of combustible materials but once again ETFE usual application is either as elevated skylight or façade which no other combustible materials surrounding or enclosed by the ETFE from top or bottom and if ETFE cell burns it will burn alone and self-extinguish itself in few seconds. Therefore, it is absolutely self-evident that ETFE usage for skylights and elevated facades is outstandingly safe in terms of fire behavior.

 

• There is no alternative to ETFE polymer which have all project specified properties- especially transparency, solar transmittance and low weight- and at the same time non-combustible.

 

• The ETFE is self-extinguished materials in few seconds, does not spread flames, does not emit considerable amount of smoke and does not form any drops after burning. It is very light material (100 times lighter than glass), melts immediately without drops and accordingly there is no risk of heavy falling objects which should be considered as super plus safety value than any other traditional transparent material.