Issue 1/2007
01/02/07
EN 81-58 Lift Landing Doors: Fire resistance test
Ari Ketonen
Historical background
The awareness that a specific method should exist to test the fire resistance of lift doors has been unquestioned since the early times when lift doors had to be submitted to fire resistance tests. At the time, enormous differences in classification were obtained in different laboratories, even in the same country and to the same national standard. Most lift landing door manufacturers export their products all over Europe and this lack of reproducibility/repeatability was experienced as a major problem.
Category: Issue 1/2007
Posted by: Editor
A team of “wise men”: B. Malhotra (United Kingdom), Prof Westhoff (Germany), Bellisson (France), and Prof. P. Vandevelde (Belgium) suggested that a method based on a canopy technique, then under discussion in ISO TC 92, be considered and tried out. This canopy was collecting the hot leaking gasses through natural convection due to buoyancy. A temperature measurement of these gasses was hoped to be suitable as measure for the leakage rate.
Working Group 3 (WG3) of CEN TC10 (Lifts & Escalators) was established under convenorship of Prof. Paul Vandevelde (University of Ghent, Belgium) to develop a harmonised reproducible fire resistance test method. The Working Group started its activity in 1983, long before the publication of the Construction Products Directive (89/106/EEC) and the creation of CEN TC 127 (Fire Safety in Buildings).
The method described by EN 81-58 was tested and refined by a group of four laboratories, with the support of the lift industry.
The four laboratories that developed the method were:
United Kingdom: Fire Research Station (presently BRE), supervised by B. Malhotra then R. Jones,
Germany: MPA-NRWF, under Prof. Westhoff, then Klingelhöfer and J. Pennings,
France: CSTB, with Bellisson, then Le Duff and Pardon,
Belgium: Ghent University laboratory (presently WarringtonFireGent), guided by Prof. P. Vandevelde, (the convenor of TC 10 WG 3).
As there were only a few regulatory requirements for thermal insulation (Italy, and France for some exceptional applications), the full attention of WG3 went to the evaluation of integrity. The original aim of the standardisation of this test method was to overcome the difficulty of “measuring” or “evaluating” integrity for doors without thermal insulation (I-criterion) where the cotton pad technique was considered inappropriate. It was namely impossible to allocate the cotton pad ignition to integrity failure or to radiation ignition, or to both. Passage of the steel rod was also considered not to be an adequate evaluation of integrity.
If thermal insulation was required, the intention was to use the “normal” ISO test method and criteria.
The first attempt was to use the canopy test, developed in the ISO-doors standard at the time. The canopy test was an indirect way to evaluate leakage through fire doors and was based on the temperature rise under a canopy, collecting the leaking combustion gasses from the tested door.
This technique was abandoned since comparative tests showed that it did not improve reproducibility/repeatability, to the contrary.
The experience with the canopy technique brought the laboratory experts to the conclusion that only a complete and direct leakage measurement could solve the problem. Additionally, the members were convinced that this measurement was better addressing the risk.
This test standard was ready long before CEN TC 127 produced its first draft on testing fire doors. The publication of the lift door test was postponed in order to allow as much coordination as possible between the two approaches. The test method was accepted in the WG and later in CEN TC 10. As can be read in the harmonised norm, EN 81-58 follows the general principle of EN 1363-1 (fi re resistance tests – Part 1: general requirements) and refers to EN 1634-1 (fire resistance tests for building doors and shutter assemblies).
Legal issues
1. Lift landing doors are requested as an Essential Safety Requirement (ESR) by the Lift Directive 95/16/EC: Lift Directive, Annex 1:
2.3. The landings at the entrance and exit of the car must be equipped with landing doors of adequate mechanical resistance for the conditions of use envisaged. (…./….)
2. Fire resistance aspects are requested as an Essential Safety Requirement (ESR) by the Lift Directive: Lift Directive Annex 1:
4.2. Landing doors, where they have to contribute to the protection of the building against fi re, including those with glass parts, must be suitably resistant to fire in terms of their integrity and their properties with regard to insulation (containment of flames) and the transmission of heat (thermal radiation).
3. Items (1) and (2) above clearly indicate that lift landing doors, including their eventual resistance to fire, are covered by the Lift Directive, and therefore their design must legally follow the Conformity Assessment Procedure specific to this Directive (see below).
Doubts on whether the lift landing doors design could be regulated by other directives have been eliminated by the official position of the EU Commission as per Document Doc. 2002/06 rev 1, and more recently, by Document LGW.2006/01 (see annex 1.)
4. The Lift Directive 95/16/EC has been transposed by all EU Member States as national legislation of mandatory application. This means also that previously existing national legislation concerning lift landing doors has to be amended to avoid internal legal conflicts. In eliminating national legal contradictions. Member States may not alter the national transposition of EU Directives.
5. In addition to the above, national behavior inevitably creates barriers to trade, which is against the “raison d’être” of the EU, and the individual commitment of each Member State. This must of course be avoided.
6. Conformity Assessment Procedure
The lift landing doors being a lift component submitted to ESR’s of Annex 1 of the Lift Directive, must be part of the Lift Conformity Assessment Procedure as defined by the Lift Directive (general rule illustrated in Annex 2).
The harmonized Standard for the fire tests of lift landing doors is EN 81-58. The use of any other standard or procedure implies the elaboration of Risks Analysis, and design approval “of the lift” by a Notified Body (under the lift Directive).
7. Position of Member States
Since landing doors, including their fi re aspect, are not listed in Annex IV of the Lift Directive, Member States (represented in the Standing Committee of the Lift Directive), Notified Bodies and Industry have approved the “Modus Vivendi” as described in REC 2/018 issued by the Forum of the Notified Bodies for Lifts (NB-L).
Major aspects of Rec. 2/018 are:
Certification
According to EN 81-58 the specification of the door, the evaluation and the results of the test, etc. are described in details in a test report. As a summary a type examination certificate similar to that in EN 81- 1/2 annex F.0.2 can be issued by the test laboratory or manufacturer which includes the name of the test laboratory, the type of door, the certification number, the name and address of the manufacturer, the references of the test method standard, the class of the door, the field of application, etc. This certificate is clearly not an EC type examination certificate.
Production control
A production control for lift landing doors is not required under the Lifts Directive. Due to the fact that it is quite impossible to check the compliance of an installed door with the type approved sample during a final inspection of a lift a production control should be established similar to the procedures given in Annex VIII, IX or XI.
Marking of the door
The door shall be fitted with a data plate with information about the manufacturer, the type of door, the certification number, the references of the test method standard, the class of the door and other relevant information. Since lift landing doors including their fire resistance are not mentioned in the list of safety components in Annex IV of the Lifts Directive they cannot be CE marked under the Lifts Directive.
Transition period
Each country will define a validity period that will correspond to the validity of the certificates delivered ante, during which the doors approved under the earlier national standards will still be valid in the country.
The European Commission, DG Entr. Concludes its “Information Note” (Doc. LWG.2006.01) mentioned here above by clearly stating that: “since the references of standard EN 81-58 have been published in the OJEU, 1 application of that standard confers a presumption of conformity with the essential requirement of the Lifts Directive.
Furthermore, national regulations should not make application of (…) standards compulsory for the testing of lift landing doors.”
(See document LWG.2006.01 in Annex 1)
The EN 81-58:2003 standard has been ultimately approved and published by all EU state members in the course of 2004 for enforcement (Publication date in the Official Journal of the European Commission 36: February 2nd, 2004).
Technical aspects
A) Why a specific test for lift doors?
1. A standard made by experts
The EN 81-58 standard has been developed by a task group of EU professionals (WG3), meeting under the specific CEN Committee (TC10), with high competence both in the fire and lift fields, therefore representing the best compromise between fire protection and mechanical operational requirements of the lift.
The CEN TC 10 WG3 committee was led by fire expert, Prof. dr. ir. Paul Vandevelde of the University of Ghent (Belgium). Experts members of CEN TC10 WG3 were from AFNOR, IBN, BSI, SFS, DIN and UNI.
2. Risk Focus
The experts of CEN TC 10 WG 3 focused on the peculiarity of the fire propagation mechanism typical to elevators. The EN 81-58 test procedure applies to all types of lift landing doors used as a means of access to lifts in buildings and which are intended to provide a fire barrier to the spread of fire via the lift well.
The following is a list of preliminary considerations:
a) Few fires start in the lift well due to the combustion of material within the lift well, which is normally limited to a few cables and a limited amount of plastic items fitted to the doors. This can be considered as negligible;
b) Few fires start in front of lift landing doors, since any material present would constitute an obstruction to the use of the lift itself;
c) Pressure differences are normally greater than the ones between adjacent rooms on the same floor, this being due to temperature differences and a chimney effect of the lift well. Under these circumstances larger hot gasses leakage rates occur than between rooms on the same floor.
Lift landing doors are therefore doors with a specific use, where the fire exposure is expected to be from a specified direction, i.e. the landing side, and where the hazard exists only subsequently to the propagation of fire into the lift well
With the normal application of lift landing doors, where the spread of fire is at the same floor level, the fire has to overcome two doors until it finds combustible material again (neglecting the small amount present in the lift well). Lift wells also have ventilation openings at the top of the shaft, therefore creating a chimney effect within the shaft resulting in an overpressure on the full height of the lift landing door.
That is why the following considerations have to be taken into account:
1) If the concern is with the transfer of fire to the lift well, then the situation is the same as with any other type of doors, i.e the transfer of fire from one to the other door side.
2) If the concern is with the transfer to another floor, then the role of the lift well needs to be considered, i.e. the nature of the construction and the effect of ventilation provisions need to be considered.
In the fire simulation, both concerns have been considered. Therefore the EN 81-58 measuring method of leakage rate of hot gasses entering the lift well and spreading fire, is a simple way to determine and classify the safety of a lift landing door. The experts have immediately identified that a required level of protection was to be considered by measuring the gas leakage from the openings that are naturally present to allow the operation of the lift landing doors and that the lift well pressures to be considered were different than with other applications. The experts therefore decided to specify a modest overpressure at landing sill level during the test. This resulted in a more appropriate and far more severe test than other methods for building doors aiming at only protecting the building from the horizontal spread of fire.
3. Reliability
The EN 81-58 standard proposes a highly reliable procedure, as the fire test is conducted by use of sophisticated equipment (a gas analyzer). The test includes recording the amount of hot gas fl owing through a lift landing door placed to protect a lift well aperture, by use of a unique gas tracer technique measuring the exact quantity of gas passing into the lift well. This method gives a precise analysis of the heat transfer through the elevator chimney, the lift well.
4. Repeatability
By only making use of calibrated measuring equipment, the test Integrity (E) results are repeatable with only minor possibility of deviation or interpretation.
B) Essentials of content
1. Compared to other norms
Various European Standards (e.g. EN 1634-1: Fire resistance tests for door and shutter assemblies) for testing doors use the following main criteria to assess the performance of a product, these being:
- Integrity (E);
- Integrity and Radiation (EW);
- Integrity and Insulation (EI).
While, for EN 81-58, the Radiation (W) and Insulation (I) aspects is essentially similar – with minor variations – to EN 1634-1 and/ or to most actual national standards, the Integrity (E) criteria measurement substantially differs as it is meant to measure the gas flow from apertures.
Most European measuring methods used to determine the Integrity (E) of a door can be summarized as follows:
a) Opening of gaps. The dimensions of these are normally monitored in different EU States by the use of steel rods, cotton pads and pilot flames.
b) Flaming on unexposed side. More than ten (10) seconds of continuous flaming is considered as loss of Integrity (E).
The EN 81-58 standard focuses on the following two aspects.
A. The Gas Tracer measures the maximum gas flow passing through all gaps (leakage) of the entire lift landing door and is measured every minute. The maximum value has been determined by the CEN TC10 WG3 Committee. Furthermore the following restrictions apply:
- The cotton pad test can not be used when the lift doors are not insulated. It is difficult to use it in a typical nonplane lift landing door.
- The gap gauges are also difficult to apply with most lift landing doors as the gaps are not through and often finish with round corners and edges.
- During the first 14 minutes, the gas flow through the gaps is measured but disregarded. Measuring integrity failure only starts after 15 minutes. Reasons for this have been given by the CEN TC10 WG3 committee as follows:
- During the first 14 minutes, the furnace is still “cold” and gaps remain very close to those set by the test sponsor, therefore giving not much sense to the reading;
- During the first 14 minutes a massive turbulence is present in the furnace, this resulting in a very unstable environment. The rapid increase of temperature while “pumping the trace gas (CO2)” in the furnace and the attempt to keep furnace pressure within the EN 81-58 prescriptions make any reading quite unreliable;
- Integrity has to be measured during fire, and at 15 minutes the furnace reaches stability in terms of temperature (ref. to the ISO logarithmic curve). The door has then been impacted with a great thermal shock and has deformed. Therefore, gas flow measures make sense as openings (gaps) have started taking place.
B. The 10 seconds flaming has been kept equal to what is described in the EN 1634- 1 standard and in most national standards as can be noticed by simple observation.
It is therefore evident that the method described in the EN 81-58 is more pertinent to protect against “the passage of gas from a hole in a chimney (the lift well)”.
C. Elaboration of EN 81-58
1. Made by major laboratories in the EU
Preliminary qualification tests, to assess the value of the EN 81-58, have been carried out by leading EU laboratories, these being:
- Centre Scientifique et Technique du Batiment (CSTB) – France
- Staatliches Materialprüfungsamt Nordrhein (MPA) – Germany
- Loss Prevention Council (LPC) – United Kingdom
- Laboratory for Fuel Technology and Heat Transfer (UG) – Belgium
2. Round Robin
A series of tests (16) have been carried out on the basis of the following matrix:
- One same door tested in the 4 laboratories to check possible variations of results;
- Different brands (by size, typology and classification) of doors, supplied by leading European manufacturers (Bolton, Kone, Otis, Schindler, Selcom, Sematic and Thyssen) randomly tested in one of the 4 laboratories.
3. Results from CEN TC10/WG3 work
The Round Robin tests conducted to validate the results of tests carried out on doors tested in accordance with the EN 81-58 standard have been very encouraging.
Results have proved:
1. That the standard is highly repeatable as none of the four laboratories has shown a significant deviation in the results;
2. The influence of lift landing door size which assisted the WG3 Team Members to determine the maximum value of leakage of hot gasses admissible into the lift well;
3. In total 16 doors from main European suppliers have been tested, 1 door type has been tested in the 4 laboratories to check possible differences in leakage. Observed differences in leakage rates on examined doors did not indicate unusual divergences or any sudden rises of leakage as an indication of sudden failure of doors during fire tests.
The Round Robin series of tests and the definition of a clear level of leakage rate of 3 m3/m/min (this being the maximum leakage measured on the “weakest” door tested, i.e. as currently sold in the EU market) have proved continuity of the use of existing EU products as tested under former (actual) local national standards. The exercise carried out by the 4 laboratories proves the new method is not going to diminish the actual level of fire protection in Europe.
The leakage rate set by the WG3 was found to be an adequate value among the tested products. It is therefore a valuable level for harmonising European products.
EN 81-58 is a better compromise than existing national or EU standards to define a proven and harmonised mean to be used by all EU State Members for protection against the spread of fire in a lift shaft.
4. The effects of Insulation on the passage of hot gasses.
It was also decided that the first 100 mm of the frame, as well as the door mechanisms were not to be taken into consideration for measuring the temperature. Due to the very nature of the lift shaft and in consideration of the innovative measuring system of hot gasses flow, the mean surface temperature of a lift landing door was found more appropriate for assessing fire transfer between floors than punctual temperature. This issue is also supported by the fact that no ignitable products can be found in the lift well in front of a landing door. As a final comment it needs to be said that the EN 81.58 approach, with reference to insulated doors, is very close to the EI2 classification as described under EN 1634.1.
The above have determined all WG 3 members and subsequently all TC 10 members to recommend the use of this methodology.
Credits: ELA thanks Ari Ketonen and the members of his Work Group for their contribution, in particular Roberto Zappa, for his technical input.
1/2007
