20 Oct The importance of testing
Ensuring the right level of performance of doors within a structure is an essential part of creating a building that is fit for purpose and can protect its occupants. Robust testing, explains Peter Barker, Technical Manager with Warringtonfire, supported by third party product certification, delivers the necessary assurance that these components will perform as required; providing privacy and comfort in general use, and most importantly, protecting the occupants in the event of an emergency such as a fire.
Doors are a fundamental component of all buildings. Depending on the type of building and the location within it, doors may need to provide safety functions such as security and protection from fire and smoke, as well as meet other important performance requirements such as durability and sound absorption. It is therefore essential to conduct testing on door products against the relevant standardised test methods to ensure they meet all safety standards and regulations, as appropriate.
In the Gulf Region, many manufacturers are now sourcing testing providers around the world who can provide both a high-quality and cost-effective service. While many test houses can offer the required service and most make similar claims about providing a full suite of testing, the actual service and cost can vary greatly. Often, a manufacturer’s testing requests are dealt with in various stages, resulting in increased fees, a requirement for more test samples, and longer lead times.
A test house that has the expertise to understand the manufacturer’s testing requirements, as well as the necessary facilities and accreditation to the relevant test standards, can provide a more efficient approach to testing construction products. And depending on the manufacturer’s combination of performance requirements, they can often devise a test programme that can provide test evidence to multiple standards on the same sample.
Initial client meeting
Prior to starting any test programme, the manufacturer should engage with the test house to explain the performance claims needed for their end market. The manufacturer should also identify the different door designs to be tested. The designs, together with the performance claims, will allow the test house to reverse engineer their requirements to devise the appropriate test specimen that will meet the objectives. It may be necessary for multiple specimens to be run through the test programme depending on the scope and complexity of the manufacturer’s product range.
Third party certification is often mandated in the Gulf Region and it may be necessary for other processes to take place prior to the testing, such as sampling of the test specimens at the manufacturer’s factory. Therefore, any certification requirements should also be discussed with the test house to ensure these requirements are factored in.
Once the test specimens have been agreed between the test house and the manufacturer, and they have been constructed with any additional certification processes, then the test specimens are shipped to the laboratory where the testing journey begins.
Three different test methods can be carried out on a single sample with the correct planning: acoustic, smoke and fire resistance testing. There are other performance requirements for doorsets, but not all of the test methods can be carried out consecutively and on the same specimen as they are destructive in nature. It is essential to use a test house that can help navigate a manufacturer through all of their testing requirements in order to meet their end goal objectives.
When testing a doorset for acoustic, smoke and fire performance, the first step is acoustic testing. This measures the ability of a building product to reduce the transmission of sound, which is measured in decibels over a wide range of frequencies greater than that perceptible to the human ear. Acoustic test results are expressed as decibels of sound reduction, i.e. by how much the product reduces the transmission of sound between rooms.
Measurements are made using pink noise which is a controlled sound, similar to white noise. Sounds are generated on one side of the test sample and measured using accurately calibrated microphones so that the level is known. It is also measured on the other side of the sample to calculate the level of noise reduction. Measurements are taken in a range of prescribed positions with background noise and reverberation times being taken into account.
The test laboratory is designed to eliminate any background noise that could affect measurements and it consists of two chambers: a source room where noise is generated; and a receive room that is used to measure the reduction of noise. The test chambers are completely isolated from the floor, the ceiling, and from each other. This stops noise flanking around the test sample so any sound measured on the received side can only have passed through the test specimen.
One of the test standards that is often used to measure sound insulation in buildings is “BS EN ISO 10140-2; Acoustics. Laboratory measurement of the sound insulation of building elements. Measurement of airborne sound insulation.” While this standard is recognised in the UK and Europe and within the Gulf Region, it is crucial that a manufacturer understands their end use requirements, including the required test method, before embarking on any test programme.
An acoustic test report will fully describe the tested element, reference the testing methodology and express the results achieved by the test sample throughout the duration of the test. The performance of the doorset under evaluation will typically consist of raw data recorded throughout the test and a calculated decibel value at 500 Hz in accordance with BS EN ISO 717-1: 2013 (Rw Value).
If the product does not meet the rating requirement during the acoustic test, this will be recorded and detailed within the test report, and in many cases is identified immediately. In some instances, it may be possible to apply minor modification to the test sample in order to obtain the required result. It is important to understand however, that if remedial work is required to achieve the desired performance, it is likely the subsequent smoke and fire testing will need to be performed with the same remedial works.
After the acoustic testing, and pending successful results, the next stage in the programme is smoke leakage testing.
Smoke testing to EN 1634 Part 3 covers smoke control tests for door and shutter assemblies, and is used to determine smoke leakage of doorsets at ambient temperatures and elevated temperatures (200oC). The test determines the leakage of cold air/hot gases from one side of a doorset to the other, representing a measure of the control of the passage of smoke in case of fire.
If it is required to evaluate the doorset’s smoke leakage performance at ambient temperatures to the EN 1634-3 standard the test specimen, as previously subjected to acoustic performance testing, will not be destroyed once smoke tested and can be used for the subsequent fire resistance testing.
To evaluate smoke leakage at ambient temperatures, the test is conducted using a specially designed smoke leakage chamber which houses a partition to install the sample within. The smoke leakage chamber is equipped with fans to control the pressure exerted within the chamber. The chamber assembly includes a pressure transducer, a flow meter and digital displays to record pressure and leakage rates throughout the test. Leakage over the perimeter length of the opening element is used to determine the results. It is possible to evaluate both positive and negative pressures at ambient temperature by simply reversing the polarity of the chamber control fan to demonstrate leakage rates at ambient temperatures from both directions, leakage readings are taken at 10 pascal (Pa), 25 Pa and 50 Pa.
A smoke leakage test report will provide the same level of detail as the acoustic testing report. The performance of the doorset under evaluation will typically be stated in terms of leakage at the prescribed pressures (i.e. 10 Pa, 25 Pa and 50Pa) as well as the leakage per linear meter of the opening element.
If a failure is observed during the smoke leakage testing this will be recorded and detailed within the test report, and in many cases this is able to be identified immediately. Like the acoustic testing, in some instances it may be possible to apply minor modification to the test sample to obtain the required result. But if remedial work is required, the acoustic testing already undertaken will likely have to be repeated on the modified sample.
The final stage in the programme is fire testing. Fire doors play a critical role in the safety of a building. Their manufacture, fittings, installation and management are a crucial part of protecting the occupants of a building in the event of a fire, and helping to protect the structure and contents.
The complete doorset, as tested for acoustics and smoke, must be fire tested to the relevant fire standard for specified timings, which vary depending on the end user requirements. These requirements are stipulated in the appropriate building regulations the manufacturer is looking to satisfy.
BS 476 Part 22 and BS EN 1634 Part 1 are often used to benchmark standards for determining the fire resistance performance of doorsets. The BS 476: Part 22 standard has been used for many years and is widely recognised around the world. The EN 1634-1 test is also widely recognised and is used to provide classifications under the European classification system, as well as for the purpose of CE marking fire resisting doorsets (in conjunction with EN 1634-3). Again, it is important the manufacturer understands the standard performance they wish to test their products to, in order to meet the requirements of the market(s) they operate in.
Both test methods measure resistance from the initial exposure to heat and flame to point of failure, while also observing the specimen’s behavior during exposure. The overall integrity of the specimen is evaluated along with its level of insulation, any deflection of the door leaf and levels of irradiance. However, there are differences in the specifics of the two test methods. The BS EN 1634-1 test standard is known to be more onerous than the BS 476: Part 22: 1987 standard, primarily due to the use of plate thermocouples within the furnace to record the furnace temperature.
A fire resistance test report will include similar detail to the acoustic and smoke leakage reports. The performance of the doorset under evaluation will typically be stated in terms of Integrity, i.e. the ability for the doorset to prevent the passage of flames and hot gasses through to the unexposed side of the doorset, and insulation i.e. to restrict the temperature rise of the unexposed face to below specified levels. Results are expressed in complete minutes.
If a premature failure is observed during the fire resistance test this will be recorded and detailed within the test report. In some instances, a sample’s design or componentry may require reworking in order to achieve the desired level of fire resistance. Again, any remedial work to achieve fire resistance will also require the completed acoustic and smoke testing to be repeated on the modified sample.
Choosing a testing provider
A test house that can provide these tests under one roof is an efficient and cost effective option, minimising time to market and saving businesses from hidden costs.
As discussed, manufacturers should explore the possibility of conducting a test programme through one shipment, one sample, one price, one contract and one point of contact. Other factors to be checked in advance are whether there is an assigned project manager; a breakdown of the programme’s timeline; whether laboratory installation is included; how progress updates are communicated; whether tests can be remotely witnessed; and how soon following completion a draft report is provided. A reputable provider, like Warringtonfire, will offer all of these services as part of the programme cost and will provide a report within seven days of the test completion date.