How compliant are your smoke ventilators in your building? ……. Will they operate the way they were intended to, when you need them most?

The True Cost of Waterproofing!
31 July, 2017

MRC Group, as a refurbishment specialist in Southern Africa, are asked nearly every time we go and inspect an existing roof, as to whether the smoke ventilators are in good working order, and will they do the what they are intended to do?

The first question that has to be asked is, what was the intention of the smoke ventilation system, only then can a judgement be made by a professional as to whether it is achieving the intention.

The second question is whether the system with all the components was actually installed according to specification and therefore compliance.

The third question is whether the system has every been adapted, damaged or maintained and whether its still complies.

This is all on the basis that the building use has remained the same.

There are a few levels to compliance:-

1. Design Compliance – Have the installed smoke ventilators been correctly designed to achieve compliance?

2. Installation compliance – Have the smoke ventilators been correctly installed with all the compliant component to achieve the design?

3. Performance compliance – Have the smoke ventilators been inspected and maintained every year to achieve the required performance when required?

All 3 levels are key to ensure the smoke ventilators perform exactly the way they were intended to perform.

Areas of Concern in associated with Smoke Ventilators:-

Over the last 4 years alone, we have undertaken over 200 technical inspections of existing commercial, industrial and retail property throughout Southern Africa. In our reports we provide full in-depth photographic reports, of which one of the areas we report to the client is the condition of the smoke ventilators. What we are about to present in this article may cause some of the readers of this article to re-visit their designs, installations and on-going annual maintenance!

Design Compliance

One of the areas we always question with the project engineer is the wind loading compliance of the smoke ventilators. Many people will ask about the imposed load i.e. the weight of the smoke ventilator on the structure, but I do not believe many people ask about wind uplift.

Roofs throughout Southern Africa need to be able to withstand an wind uplift from 1.6kN/m2 to over 2.2kN/m2 depending on the location, orientation and height of the building. We undertook the exercise of checking with every manufacturer the ability of the smoke ventilator to withstand the same wind uplift loads as the roof. We were surprised (horrified) to note that the certificated loads ranged from 300N through to 2.3kN, this was an exemption range. In most cases the manufactured smoke ventilators failed short of the wind uplift loads of the roof system.

The dangers of a vent that doesn’t comply with the same wind uplift loads as the roof sheeting system, is that the blades within the smoke ventilator can be sucked out, but far worse is, that the blades can be distorted and therefore jam the adjacent blades and can cause system failure when the vent is required to open.

Regarding airflow through the smoke ventilator we also noted that most of the certificates we analysed, were tested on unobstructed airflow. Many of the smoke ventilators we see on the various sites, as we inspect the roofs, have bird and security mesh within the unit. The introduction of these items will reduce the amount of airflow through the unit and therefore the required smoke ceiling will not be achieved causing death to the occupants through smoke affectation. Looking through the certificates these extra items are not generally mentioned.

The area of sealants around the smoke ventilation systems is not as well specified as they should be, with vague details leaving the door open to supply and install sealants which are not able to withstand the heat temperatures from the warm smoke should there be a fire within the building.

Why is this so important? There as been examples of the sealants of smoke ventilation systems in use melting. This is key, because the sealants are there to ensure a good seal on the units to move the correct about of smoke filled air from within the building.

So in every case, mentioned above, we ask the question are the smoke ventilation systems compliant? What will happen within the building if there was a fire? Will these un-compliances cause death and will insurance companies pay the client if the building fails to control the smoke and fire?

Installation Compliance

In most cases, the installation of the various specified systems are not installed by the manufacturers, even though the manufacturers of the system submit the quotation, with the installation element sub-contracted out.

How often is installation compliance checked by the manufacturers? In most cases the project managers have multiple sites to manage, and to ensure that every element is installed correctly is nearly an impossible task, unless a full time individual project manager is insisted upon.

On a lot of the roofs we have inspected, the motors that have been installed are not compliant for external use, with motors fit for internal use almost the norm.

The cabling to ensure power to the motors should be impact and heat resistant with a high temperature threshold, however the roof inspections we have undertaken shows that the original installer, who has left the cable open to the elements of heat, UV and water, has little understanding of these matters.

So in every case, mentioned above, we ask the question are the smoke ventilation systems compliant? What will happen within the building if there was a fire? Will these un-compliances cause death and will insurance companies pay the client if the building fails to control the smoke and fire?

Performance compliance

Following correct installation of the specified smoke ventilation system, a guarantee is issued. It is normal for this guarantee on the system to state a period of 12 months, which is horribly short of the 10 – 15 years material guarantee of a normal metal roof system.

So where does this leave the client?

It is the client’s responsibility to inspect and maintain the smoke ventilation system every 12 months by a competent contractor. The inspection and maintenance needs to be correctly reported to ensure that all elements are correctly and accurately replaced where necessary.

What is alarming is that in many leases of multiple tennant buildings, the responsibility in some cases is actually left with the individual tenants on the individual units, leaving the whole smoke ventilation system exposed.


With more and more fires throughout the world of industrial, commercial and retail property, the issue of smoke ventilation compliance will be discussed over and over again.

Will the un-compliance of the smoke ventilation system in your building, cause the death of an occupant?

As part of our building refurbishment service of inspection, installation and maintenance, MRC Group is leading the way in changing the industry, providing a full turn-key solution that protects both the building owners and the occupants. – Operating throughout Southern Africa

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