Key Specifier Concerns

To ensure the design intent of a building is not broken, product selection criteria have to be carefully thought through. Specifiers will want to consider such issues as the potential of corrosion, air tightness, the sustainability of the building, energy consumption, not forgetting meeting building regulations. Here are some key tips to help you specify fasteners and hinges.

Specifying the right product

Advice on specifying the right fastener

Fasteners and sealants make up only a small amount of the building cost, but cutting corners and saving money on the fasteners could mean larger costs later on.

Using cheap imported fasteners often leads to dissatisfaction because of poor fit, poor finish, poor performance, high wastage levels, a shorter life and high remedial costs. A failed air test alone could cost more to sort out than the savings made by buying cheap.

The only way to ensure you aren't paying unnecessary costs down the line is to use a quality component in the first place.

Make sure you use the right fastener for the right job and installation will be right first time.


On the surface, it may seem as though all fasteners are the same, no matter what they are made from. However, small differences in the alloys dramatically affect the steel’s performance and also its cost. Inferior fasteners will corrode, rust and fail within a very short period of time leaving you responsible for costly remedial works under warranty.

There are essentially three types of stainless steel materials you should know about. They are Austenitic, Martensitic and Ferritic. However, fasteners are principally manufactured from two stainless materials: Martensitic and Austenitic stainless steel.

Beware of Martensitic stainless steel fasteners. Despite their highly polished appearance, martensitic or modified martensitic fasteners can fail without warning and don’t conform to BS5427:1996. They are susceptible to sudden Hydrogen stress corrosion and can fracture within 12 months of installation.

Carbon steel fasteners have no natural protection against corrosion. In order to guard against corrosion they must be protected with an anti-corrosion layer, such as paint or plastic films. These protective coatings only offer temporary resistance against corrosion and can be easily damaged, especially during installation. Carbon steel fasteners generally have a warranty period of up to 10 years.

Care should also be taken when selecting the correct bimetallic fastener. Stainless steel wire costs more, and less stainless steel content means a cheaper product. Many importers will supply fasteners that contain up to 50% carbon steel content at the self drilling end. It is, however, vital that you ensure ALL threads above and immediately below the purlin are composed of fully Austenitic stainless steel of the bi-met design. If not, then the carbon material will corrode and subsequently fail.

Some contractors will use nitrided austenitic stainless steel fastener, but they offer little more corrosion protection than carbon steel alternatives. These fasteners achieve hardness for drilling without incorporating a Bi-Metal carbon steel drill point. The nitriding process withdraws chromium from the surface, reducing corrosion resistance. To combat this, fasteners have a zinc coating which will be damaged during installation, severely limiting its corrosion resistance.

SFS products use austenitic stainless steel to ensure that the buildings they are used on won’t fail due to corrosion. Austenitic stainless steel fasteners have an inbuilt Chromium Oxide layer that seals the metal surface, dramatically reducing corrosion. They need no further protection in all but the most aggressive environments. Increasingly, SFS's range of fasteners can be bought in A4 austenitic stainless steel and can be provided with a 40 year warranty dependant on the buildings' location.

Ensuring that you have specified the right fastener for the job can be tricky but by using stainless steel fasteners you are genuinely reducing the chance of corrosion and the failing of a building.


An air test is the key test to check how airtight a building is and whether it passes or fails the regulations. A failure at this point can be damaging for all parties involved, often resulting in major rectification works. But what is the air test?

The air test is conducted when the building project is completed. All windows, doors and other intended apertures (basin wastes, overflows etc) in the building are sealed off. Air is pumped into the building until the pressure difference between the inside and outside is 50 Pascals. This pressure difference is maintained for 1 hour by running the air pump as required. The amount of air used is measured and recorded; it equates to the amount of air lost through leakage.

The maximum permitted air loss from the building is 10 cubic metres for every square metre of wall, floor and roof. For a good size industrial unit, 10m³/hour is roughly the equivalent of changing the air within the building four times in an hour.

Smoke generators are sometimes placed within the building so that air leaks can be traced. 50 Pascals is a very low pressure difference, for example a typical car tyre is inflated to about 2 bar - 200,000 pascals.

Complying with building regulations

Building regulations are becoming stricter and stricter with an emphasis on ensuring the building meets regulations for 25 years of its life. This is hard to ensure. You need to design for durability but also make sure that your design and specification is met. Finding the right products for the right job is the key to meeting regulations. But it is also important to check for meaningful warranties on products to protect against any comeback on failures in the future.

Most remedial works and premature failures are caused by poor fixing and the use of the wrong or substandard materials. Do insist on good workmanship, check for quality standards, check for meaningful warranties, check for trade association memberships and always stick to reputable companies, but still vet the proposals before and during the installation process. A few hours spent checking at this stage could prevent an expensive, unexpected and difficult repair later.

Using our products ensures that you get the right product for the job, with ease of installation and on-site support. We also have installation videos available for roofing contractors to ensure that installation is right first time.

Part L2

Airtightness is a key consideration of Part L2 of the Building Regulations for England and Wales, which was introduced in October 2006 to help address energy efficiency requirements in non-domestic buildings.

A prime focus for the regulations is providing building managers, landlords and tenants with detailed and accurate information about energy usage in their buildings to enable them to identify areas where energy is being wasted and where there are opportunities for reducing energy consumption.

The latest amendments to the 2006 Part L2 came into effect in April 2016. For more information about Part L2, visit

Secured By Design

In 1989 the Association of Chief Police Officers established Secured by Design (SBD) which focuses on the design and security for new & refurbished homes, commercial premises and car parks in addition to the acknowledgement of quality security products and crime prevention projects.

In essence, the initiative is about 'designing out crime' to reduce the vulnerability of people, property and businesses to crime by removing security issues that may be inherent in existing product design. SFS intec is committed to keeping you and your work compliant with regulations. We do this by working with SBD to design hinges that exceed current standards and are accredited by Secured by Design.


SFS intec hinges are PAS024 certified. This means that our hinges have been tested on doors that are monitored by a UKAS accredited certification body to ensure compliance with PAS 24:2012 - which ensures enhanced security performance requirements for doorsets and windows in the UK, referenced in BS 6375 Parts 1, 2 and 3.

SFS Group Fastening Technology Ltd.
153 Kirkstall Road
UK-LS4 2AT Leeds
T +44 (0)330 0555 888