Correct tools for assurance of properties of building materials

It is already more than 25 years since World Trade Organization has been working to making markets more open. Today 99.98 % of world GDP is brought about by 99.35 % of world population representing countries who are members of WTO. Access to greater number of suppliers across the world has given a big push to innovation and creativity in the manufacturing sector. But this has also lead to ever increasing complexity of supply chains of raw materials and products and solutions.

Products (example Mobile Phones) and materials now have multi-tiered suppliers across countries. Suppliers of building products and materials often be from several countries. Imagination of architects have challenged the manufacturing sector to innovate; leading to an increase in the complexity of supply chains. The materials supplied into buildings often come from countries which not only have different mandatory compliance requirements but also have different environmental and climatic conditions.

Architects, Consultants and Contractors often struggle to balance fulfilment of creativity with compliance to local environmental and mandatory requirements for the elements of the buildings. They often resort to the Testing, Inspection and Certification industry to help them navigate this maze. But the nomenclature used by this industry is often misunderstood.

What is a test report?

A test report is snapshot of the behaviour of specific properties of a given sample of material or system. The results are only of the sample tested and it should not be automatically considered representative of any other supplies without measures to confirm that it is.

A valid and usable test report must capture the following:

1. Accreditation or authorisation of the lab for conducting the test. Bodies like the United Kingdom Accreditation Service (UKAS) or the International Accreditation Service (IAS from the US), many of them formerly government bodies, provide laboratory accreditation. The lab is required to follow a uniform quality management system and to demonstrate its competence in conducting the tests within its scope. These requirements are set out in the international standard ISO 17025, standard for the general requirements for the competence of testing and calibration laboratories. This is comparable to ISO 9001 for manufacturers. Accreditation bodies belong to umbrella organisations such as ILAC which have a system of mutual recognition for their members. An acceptable accreditation body will therefore be a signatory to its umbrella organisation’s “mutual recognition agreement” (MRA) or “multi-lateral agreement” (MLA).
2. It should state the condition and origin (or traceability) of the sample used to conduct the test. This often supports the certification process which provides a better route to validate the conformity of supply of products and materials from manufacturing locations. This is explained at length later.
3. The date of the test report and the version of the test standard against which the test has been performed must be stated. Reports of specimens tested a long time ago – several years, for example – or according to an older version of the test standard should be approached with caution.

Readers of test reports should not confuse the usage of the term “validity of test report” to link with the manufacturing date of the material supplied. The validity in months or years mentioned in test reports is only done keeping in mind a revision cycles of the test methods. Hence, a report issued in March 2016 which could be valid for three years does not mean that all the material manufactured until March 2019 will be the same as tested. This only means that the test standard used to conduct the test, say ISO 1716:2018 (Reaction to fire tests for products – determination of the gross heat of combustion (calorific value)) might get revised by 2021.

Caveat emptor

So how does the contractor or buyer of building material get the assurance that the material that will be supplied will behave as the sample produced for the test report? After all, this test report may have been submitted as part of the qualification submittal or be part of claim on a product brochure.

There are two valid means used to get this confidence:

The first relies heavily on mutual trust between the product’s seller and the buyer of the product. Here the seller (sometimes) gives a copy of a test report (which may or may not cover the three points outlined above) and submits evidence that the manufacturing facility follows some Quality Management System (for example ISO 9001).

The second method, Certification & Listing, is relatively airtight method although by no means fool-proof. Certification and listing relies on a third-party organisation (certification bodies or CBs) whose job is to methodically offer tools to quantify this trust. These CBs need to have an accreditation as per ISO 17065 to be in a position to offer these services of certification and listing. To establish the much-needed trust, they usually follow a four-step process:

• Step 1. A qualified staff member witnesses the production process of the product/material that will be tested. The process and raw materials are mapped and the sample is marked for traceability.
• Step 2. The marked samples are tested to produce a test report complying with the three points pointed out earlier.
• Step 3. After a successful test the CB starts to regularly audit the quality control processes at the given manufacturing location. This is done to ensure that the products which are shipped with the traceability of certification (certification mark/unique ID/number) are manufactured in the same way as the witnessed samples were made.
• Step 4. After the success, the CB lists the name and identification of the product/ material packing along with manufacturing location and details of the fire tests the material is complying with on their public domain website. This acts as a buyer’s guide and an important tool for buyers to verify the claims in product brochures or price proposals.

A table from ISO 17067 which describes the fundamentals of product certification and provides guidelines for understanding, developing, operating or maintaining certification schemes for products, processes and services is also shown in the Figure 1 This table is also used to choose the conformity method in the UAE Fire and Life safety Code of Practice

Using certification correctly

An increasing number of product recalls worldwide is proof of how small slippages in procurement or quality assurance can have big detrimental impacts.

Genuine certification leads to a clear and public listing showing compliance parameters as well as traceability of material origin using markings on the product to distinguish the supply from others.

In case a buyer (Contractor) cannot match what material is received against the compliance evidence submitted at the time of offer they need to raise a flag. It is like a person allergic to (say) nuts buying and consuming food products whose label says, “Contains nuts”.

Validating Designs

Bespoke designs are the new norm. Competition and technology have helped the construction industry (often) overcome the economies of scale such that custom made interiors, exteriors or even structures are not more expensive. There are several parts of a building which are always custom designed. Testing and validating mock-ups of designed systems for many combined properties is not new. Designed building envelopes have been tested for Air/Water leakage and even acoustic performance since decades now. But the implications of incorrectly using and interpreting the results of mock-up tests became more glaring when the link between mock-up fire tests and high rise fire accidents were analysed more in the recent years.

Correctly using Mock-up tests

Materials produced in factories can be tested and certified to provide the assurance or repeatability of performance of their properties (Mechanical, Physical, Acoustic, Fire, Etc.) But when different materials are brought together in a specific configuration, several properties of the system need to be evaluated. A mock-up is built to check how the designed system is performed. But only limited details can be mocked up as it is often too expensive/ impossible to mock-up every variation in a system design. Also the workmanship of the installation is often given a lot of attention as it has to be tested. Hence it becomes critical that it is replicated at the project (site)

These limitations are often covered using below

1. Establishing a scientific correlation between what is mocked-up and all the possible variations of the design needs a subject matter expert who is familiar with the complete project.
2. Using qualified inspectors to ensure replication of workmanship and design at the project site.

Lacking this assurance is like training and coaching an individual on a subject and sending another to sit an exam on the same subject. Results can often be equal to wasting the time, effort, energy and money spent of assuring the supply chain or materials and validation of designs using mock-ups.

Just like the accreditation of testing labs and certification bodies are critical, ISO 17020 (Standard for Conformity assessment requirements for bodies performing inspection) provides the much needed tools to validate the competence and independence of such an Inspection body.

Supply Chain Challenges

In the dynamic world we operate in, it is common for realising gaps in conformity last minute. There are occasions when new compliance requirements come in effect because of new learnings from accidents (example cladding materials). The cost of attaining assurance via normal routes of testing and certification could be very high in cases where the bespoke materials produced are very small in volume or when materials have already been procured or installed.

Quality assurance of bespoke material

It is common that interior fit out, carpets and designed finishing is custom made for specific projects. It can often be impractical to bring the production process of such materials under the four step process of certification explained earlier. The most commonly followed way out is to rearrange the responsibility of the audit or assurance process of the supply chain. In the traditional model, the certification body takes the ownership of auditing the production processes of manufacturing locations regularly to ensure repeatability of production. In certain cases it is easier for the consultant take on the responsibility by randomly selecting samples from the supply to send to accredited labs for testing. This consultant then takes on the liability of assurance of the supply of the material. As they are (often) the independent party between the buyer (Contractor) and the seller (Material Supplier) and they would be responsible assurance of the project, they will ensure that representative sample is sent to the lab.

Conclusion

The standards ISO 17025, ISO 17065 and ISO 17020 provide the tools to validate the efficacy of the independent agencies used to create the much needed reliance in construction. These are not only used by government regulators to implement technical laws, but also used to contractors and consultants to create better specifications and drive them effectively to reduce liabilities.

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