Fire Resistant Testing - Past, Present and Future.

North American History and UL’s Role in Fire Door Testing.

It is fitting that the development of the early test methods for fire doors in the US occurred in Chicago, Illinois as the city was the site of one of the more economically devastating conflagrations that occurred in the US during the nineteenth century. To showcase the city’s growth as an economic engine in the US and its ability to recover from the Great Chicago Fire, Chicago hosted more than 21 million visitors during the World's Columbian Exposition that was a World’s Fair held in 1893. The fair showcased many new technologies to the world, including electricity.

With electricity, came the proliferation of DC circuits and the new, higher voltage AC currents, which subsequently caused a great deal of concern and many fires, including several in the Electricity Hall at the Fair.

This growing fire risk due to electricity was subsequently identified by William Henry Merrill, and later, the insurance underwrites located in Chicago. Mr. Merrill felt that this new technology could be safe when handled with the proper care and understanding of its potential hazards. With this goal in mind, Merrill conceived of the idea of an independent testing facility that could provide expert opinions concerning fire hazards and certify electrical devices. This facility led to the founding of UL in 1894 when Mr. Merrill established the Underwriters’ Electrical Bureau and Electrical Bureau of the National Board of Fire Underwriters. Within five years, the organisation moved into other areas of testing and evaluation including fire extinguishers and more importantly for the scope of this article, fire doors.

The start of fire door testing by UL began in 1901 when the organisation built its first fire testing furnace and changed its name to Underwriters’ Laboratories Inc to reflect the larger scope of the organisation. The first UL specific test standard for a product was issued only two years later when the first Standard for Safety, “Tin-Clad Fire Doors” was issued. This Standard continues to exist today, one-hundred and eight years later as ANSI/UL 10A that still concentrates on tin-clad doors. The result of these events have meant that UL has been tightly linked to the testing and certification of doorsets in the US and Canada since the early days of the company.

North American ‘Codes’

Parallel to the development of UL was a development of various North American groups and associations. These became responsible for developing and owning the codes that were being written as building progressed in North America. They included many aspects of building regulation from plumbing to electrical aspects and, critically, fire safety aspects also. The regulations were generally written by consensus groups, including the input of manufacturers, and then adopted by government groups.

Briefly the main groups that came into being over the past one hundred years and still have relevance in current codes are:

• International Code Council – ICC.

• National Fire Protection Association – NFPA.

• National Building Code for Canada – NBCC.

• American Society for Testing & materials – ASTM.

It is these codes that form the basis for building safety in North America, and increasingly are used around the world for new buildings.

European History

In many cases, for manufacturers of construction products selling into Europe, the system has been far from clear – especially fire doors. The individual countries have implemented national regulations based upon national tests and in many cases there were differences in the requirements; some of these subtle, some differences more significant.

With the introduction of European harmonisation via the Construction Products Directive certain products were able to obtain a CE mark to show compliance with European directives. In order to obtain a European certification mark (a CE mark) for fire doors a producer will need to show compliance against a product standard.

This has been long in the making and the estimated completion date or ‘date of availability’ has been pushed back a number of times. It seems, in many cases, producers have lost all faith in the system. In fact, while many countries have moved their Regulations over to be based on European Test Standards, the complete system of certification based on CE marking has been completely absent for fire/smoke doors. This hiatus is about to change as the Product Standard is expected in 2013. Together, with the advent of the Construction Products Regulation (CPR) at a very similar time to the completion of the product standard (EN 16034), producers of doorsets will be moving towards European certification based on a CE mark. To reiterate, this will become a reality in the near future and the industry is beginning to gear up to address the demands that this brings.

So how do the two systems compare as far as fire doors are concerned; the long established North American based codes and the soon to be introduced European system for CE marking based on EN 16034?

Test Methods
 

Historically there has been no firm connection between the development of the North American based codes and the European system. This is despite both regions being involved in International Standardisation activity via ISO. To date any harmonisation activity has not reached as far as code development and certainly not as far as fire/smoke doors. This has led to differences in the test methods that underpin both systems.

The heating regimes for the test methods are both based on ISO 834 from many years ago but there the similarities end. The U.S. codes reference ANSI/UL 10B & ANSI/UL 10C for the fire testing of door assemblies and Canada uses ULC/CAN4-S104. The ANSI/UL 1784 standard is used to test smoke control door assemblies for the US market since Canada does not require this type of testing for doorsets. These tests contain major differences, which translate to critical aspects, from the European test methods; EN 1634-1 and EN 1634-3 for fire and smoke doors respectively.

Two of these critical aspects are the pressure within the furnace chamber, which can be positive or negative, and the use of a hose stream test to measure the remaining ‘robustness’ of the door after the fire test duration.

Furnace Pressure

UL10B & UL10C are similar to each other in many ways, but the key difference is furnace pressure, which differs in that UL10C requires a positive pressure above 1 metre height (neutral at 1 metre above sill) whereas UL10B and ULC/CAN4-S104 requires the furnace chamber to have a neutral pressure at the top of door assembly. The furnace pressure can have a major effect on the performance of the doorset, particularly for timber based doors, so a degree of consistency would be a major benefit to those manufacturers who need to develop doors to both sets of codes.

The negative pressure within the whole of the furnace chamber is something that has never existed in the European Standard. In EN 1634-1, the furnace pressure is neutral at 500mm; dissimilar to UL10B, UL 10C and ULC/CAN4-S104! The negative furnace chamber pressure is being slowly removed from codes in the US although it still exists in some locales, which have not adopted the IBC and in Canada, which does not utilise positive pressure testing in any form for doorsets.

Hose stream

The hose stream test is intended to ensure that fire resistant building products cannot easily be penetrated by other building materials or furnishings during a fire. The test, in the form of a stream of water, at a constant amount of force, is uniformly applied to all portions of a door, wall or glazed assembly for a calculated duration. The duration and pressure of the hose stream test increases with time as products rated less than two hours are subjected to a 207 kPa (30 psi) hose stream and more than two hours are subjected to a 310 kPa (45 psi) hose stream where the pressure is measured at the base of the nozzle. The duration of the hose stream increases based upon the size and rating of the assembly as the duration is calculated using factors that increase with time and the square area of the assembly being tested.

The hose stream test has been conducted by UL since the 1920s when it became a replacement for the sand bag pendulum test. Originally, fire resistant doors, glazing and walls were subjected to the impact of a sand bag swung into the assembly to ensure that the product would not break after being exposed to the fire test. Product manufacturers took note of the sand bag test and began to reinforce the area of the impact to ensure better results. Seeing that products were being designed to meet the impact and not the intent of the standard, which was to ensure that the product was a rugged barrier over the entire product and not just one area, the hose stream test was developed.

This means that doors and other products that are to be used in vertical applications must be tested to the hose stream test to receive any classification to a UL or ULC Standard. The only exception permitted is for 20 minute rated doors intended for use as smoke barriers and installed where the IBC has been adopted.

The implications are that products designed for use outside North America often need some redesign or additional features added to achieve similar ratings in the US to what they might possess in other markets. As a result, ratings do not exist for products such as 60 minutes Integrity only toughened glass or unlatched doors held closed only by closers. Additionally there is a need to choose hardware products and components much more carefully and all tests for hinged door leaves are usually conducted with positive latching devices installed.

Installation

Another significant area of difference is in the aspect of on-site work.

In North America, and other countries that reference the International Building Code, NFPA 80 (Standard for Fire Doors and Other Opening Protectives) and NFPA 105 (Standard for the Installation of Smoke Door Assemblies) have become widely referenced and widely adopted as installation standards for fire doors, fire windows and smoke door assemblies. The IBC, NFPA 101, local regulations and UL Certification Information all directly reference these documents as they are the definitive North American standards on product installation and use.

These standards cover requirements for marking, regular door inspection and maintenance, common installation methods, common industry terms and hardware requirements for products. These installation standards are specifically referenced in NFPA and IBC Code Documents and are seen as “best practices” for fire doors and smoke doors and they also define component use for fire rated door and window assemblies. They are used as evaluation criteria by Authorities Having Jurisdiction (AHJs) to determine compliance for proper installation and therefore act as a primary building code regulation for fire doors.

Europe has not gone as far as the IBC and NFPA with the requirements for installation of fire doors, preferring to leave this to national regulations rather than make it a European matter. The European ‘codes’ address products up to the factory gate and once outside the manufacturer, they become subject to local regulations. As a result there are many differing installation requirements across Europe for fire/smoke doors ranging from quite firm and tight requirements based on the certification of the installed assembly, involving independent third-party certification, to very little or no control over the installation. There are moves to change this. For instance in the UK there is already a move for much tighter controls and, although voluntary at this stage, take-up of the voluntary certification for installation seems good despite many years of false dawns.

For the time being however, the differences remain strong between the two systems as far as installation of fire doors is concerned.

UK system

However, there are a number of complications – not least the culture of doorset fabrication in UK and some other countries. In these cases, doorsets are defined as a complete doorset including door frame, door leaf or leaves, building hardware, seals, glass etc., is often not what is bought. The complete doorset often only comes together on-site, that is at the time of installation. As the product standard EN 16034 only covers complete doorsets for CE marking, the UK type situation of components being placed on the market means that most ‘doors’ will be able to be CE marked unless this is addressed by the installer. Given that there are not that many specialist installer companies for fire doors it is difficult to understand how these will be covered. This leaves a situation in many countries where some doors will be CE marked, that is, subject to the EN standards and the increased rigour above national test methods that these bring, and some being based on national standards as they are not able to be CE marked. A situation that many people would agree is wholly unacceptable in moving towards a level and transparent marketplace.

The Future

So now it should be clear to you why the codes came into being, which bodies are involved in the development and ownership of the codes and how they will impact on doorsets.

For the future, it is clear that these ‘International’ codes will continue to be used for countries outside of North America as the buildings are built by North American finance, designed by North American trained architects, influenced by readily accepted and consistent ‘American’ or ‘North American” (usually NFPA or IBC sourced) codes and standards – which are increasingly becoming true International codes and standards.

Test Standards in North America will continue to be developed to align with North American codes. These Standards will continue to differ from European standards. There is no intention or move to harmonise the US based codes with European regulations. This means that the need for certification of doorsets against the Standards referenced in the ‘International’ codes will continue and, as the US codes are often used in emerging nations, their use will increase, especially in Middle Eastern and Asian countries. It is likely then that if you export you will continue to be asked about meeting these requirements.

To address these difficulties in seeking product certifications for different markets, UL has developed a combined fire door test method that can be used to test against US and EN standards in one test program. This means that a producer of fire doors can conduct a fire resistance test and use that test evidence for UL certification purposes as well as CE marking (when it arrives for fire doors) and even some national Standards gaining multiple results at the same time.

Contact: For further information, go to www.ul.com

(Author)

Matthew Schumann & Rob Wakefield