Modern Building Services

MODERN BUILDING SERVICES SEPTEMBER 2022 25 FEATURE INSTALLER’S VIEW 2. Incorrect anchor selection Mechanical & Resin Anchors are a small but very important part of an installation. If the anchor fails, the entire installation can collapse. Incorrect anchor selection is one of the most common causes of anchor failure, alongside incorrect installation and specification changes during the project. According to the BS8539:2012 code of practice, there are six factors that must be taken into account when selecting an anchor fixing: • Substrate type • Loadings • Environment • Type of installation • Type of anchorage • Approvals “The most common problem we see is insufficient or incorrect consideration of loadings and forces, resulting in the selection of the wrong anchor.” Understanding how the load affects an anchor Unless an anchor has been ETA approved it is unknown how the anchor will perform under a given load. There are several different types of load to consider when selecting an anchor. • Static and dynamic loads - A static load is the weight of an unmovable object on a surface. A dynamic load is a load that has changed in either size, position, or direction. • Applied load – The applied load is the actual load intended, by the designer, to be applied to the fixing (can be referred to as unfactored load). • Direction of the load – The direction of the load can derive from tension (forces at a right- angle to the surface) or shear (forces parallel to the surface) or both. • Duration of the load – For example, will an anchor be under a certain load for a short amount of time or long-term? As a result, BS8539:2012 recommends that only anchors with ETA approvals should be used. An anchor that has undergone ETA approval has been subjected to a whole range of testing programs to ensure the safety and reliability of their performance in a multitude of situations. ”To use an unapproved anchor is a risk wewould not recommend taking. ETAs provide all of the load and performance data for the anchor, making it amuch safer option.” 3. Use of wood block insulated pipe supports With the Government’s drive towards net-zero carbon emissions by 2050, raising the thermal efficiency of buildings is now a key priority. Insulated pipe supports sit in- between the pipe itself and the pipe clamp, and are used onHVAC systems to maintain thermal performance. Historically, wood blocks have been a commonmethod of insulating pipe supports. However, the BS5970 code of practicewas updated in 2012 to state that “wooden pipe supports should not be used” because they do not offer adequate thermal bridging or vapor barrier. “Despite the recommendations of BS5970, it is not uncommon for us to visit construction sites today, and still seewood blocks being installed.” Phenolic insulation is now a widely available alternative to wood blocks which offers far superior thermal insulating properties. “We would recommend the use of phenolic foam over the alternatives as it has a high insulation value in comparison to alternative pipe supports.” 4. Products incorrectly installed Installation methods and procedures are important to ensure that products ultimately perform their role effectively. This applies to everything from anchors to phenolic pipe supports and fire stops. A product incorrectly installed can result in failure to get sign-off on the installation and costly rework and ultimately lead to failure of the installation if not corrected. Some of the issues we have seen on-site include: • Fire sleeves installed before fire batts are in place • Mechanical anchors over or under torqued • Phenolic pipe supports not installed with the joints in a horizontal position It’s important to follow manufacturer’s guidelines shown in installation instructions provided with the products, and for ETA-approved products, additional and detailed installation instructions are included in the ETA documentation to ensure that when correctly installed, the product performs as expected. “All too often the installation instructions are overlooked for speed or because there is assumed knowledge on how products should be installed.” Taking a little time upfront to train installers in the correct installation methods can pay off in the long run. If in doubt, many manufacturers offer onsite toolbox talks and training to install products correctly. More information can be found at www.walraven.com “All too often the installation instructions are overlooked for speed or because there is assumed knowledge on how products should be installed.”