Typically sited in cramped locations at the base of buildings with hundreds of people living or working above, power components in high rises simply cannot add any fire risk. Independent certification is the most reliable way to ensure power components for high rises offer the safety levels required.
It is the contractor building a high rise who is ultimately responsible for the safety standards in that building – both in public perception and for any potential legal liability. In this, they are guided by local building codes. While contractors are experts in the construction requirements of these safety regulations, power issues are also increasingly important. This is an area contractors are not familiar with. And the risks here may not be immediately apparent.
International standards form the basis of most building codes’ safety requirements for power components. By choosing components that meet those standards, contractors can go a long way to creating a safe building. But it isn’t enough to just assume a product meets the standard or that meeting the standard alone delivers a sufficiently high safety level. That’s why independent certification and additional testing beyond standards are invaluable tools for component manufacturers looking to do successful business in the highly competitive construction sector.
Perhaps the three most relevant component types for high rise designers and builders are distribution transformers, medium-voltage switchgear and power cables. In all cases, the principal area of concern is fire: whether a component starts a fire and how it will behave if a fire breaks out nearby.
Transformer fire resistance
Generally, building codes specify the use of dry-type (cast resin) distribution transformers to reduce fire risks. These are less likely to cause or accelerate a fire than oil-based alternatives. However, fire behaviour is still a critical concern.
Dry-type transformers are covered by standards such as IEC 60076-11. This standard also defines special (optional) tests for verifying fire behaviour. In a recent analysis of test results from KEMA Laboratories, around 50% of the dry-type transformers we tested initially failed these fire behaviour tests. If these failures had occurred in high-rise buildings rather than the safety of our test facilities, the consequence for the building and its occupants could have been catastrophic.
For switchgear in high rises, the key characteristic is its ability to withstand internal arcing. This is even more true in high rises than in typical grid applications. Limited space for infrastructure means switchgear is often located in very small rooms in buildings. This brings some unique challenges: technicians carrying out maintenance must work in close proximity to the equipment and any pressure waves caused by internal arcing can travel much faster in confined spaces. Hence there is much greater risk of injury to people and damage to the building.
The enclosed switchgear typically used buildings are covered by standards such as IEC 62271-200 and IEEE C37.20.7. These standards look at potential arc exposure to the public and to technicians carrying out maintenance. For high-rise applications, exposure for technicians is typically more relevant and should be a key consideration in the procurement process.
Preventing toxic smoke
Electricity cables run throughout the building. The ducts and conduits carrying them link floors creating channels that can spread dangerous smoke very effectively in case of a fire. So, while cables are covered by a number of different standards, when deploying them in a high rise, special attention should be paid to their fire resistance capabilities. In particular, the risk of the cables’ PVC sheathing catching fire or releasing toxic gases should be verified – both for single cables and bundles. These tests may not be included in a standard type test programme, and contractors are strongly advised to check if they have been performed before procuring cables for a high-rise development.
To be confident in the safety of their building and to protect themselves from any liability if the worst does happen, contractors need to be sure that all these tests have been carried out correctly and impartially. Independent certification by a reputable testing organization such as KEMA Laboratories is the only real way to build that confidence.
Our industry-leading testing laboratories have the power and facilities to carry out all the standard and additional tests required to ensure a component is safe enough for use in a high-rise building. And our global reputation for impartiality and reliability means KEMA Type Test Certificates are renowned the world over as a mark of quality and safety. As such, they give contractors greater confidence in the components they are buying and allows manufacturers to compete against the price pressure of lower quality rivals.