Main image: The Firs Rosebank

A good building depends on wonderful views and good design. Glass, as a construction material, is the only way to connect the external and internal environment, whilst keeping out the unwanted elements.

This permanently visible barrier can be moved but uniquely when closed allows you to see outside, bringing the outside, inside. But are we committing “victimless” crimes?

According to Nick Wright from Nick Wright Consulting, people will spend money on vehicles, technology and marble in their kitchens, but they balk at sending money on adequate, cost effective, high-quality window and door systems.

Compliance to National Building Regulations (NBR)

Nick says inadequate compliance to the NBR include three main issues for glazing installations:

1. Energy efficiency

We have drastically changing weather patterns fuelled by global warming – 50 degrees in Paarl, killer floods in KZN. Academic papers from the South African Weather Service confirm extreme weather (https://www.mdpi.com/2073-4433/11/7/712). Therefore, energy efficiency (part XA) became part of the NBR in 2011 to reduce the production of greenhouse gases. 10400 XA requires controls for shading, insulation and air leaks to glazed windows, doors and rooflights. We tend to still think that European weather is extreme, when in actual fact, so is South African weather. So putting in cheap, non-conforming windows doors and roof lights is not a “victimless crime”

2. Not submitting plans: Do councils regulate this?

Building regulations are there to make a building safer. Before renovations can proceed, a form must be submitted to the council for approval. NBR A22 (1)(a).

“For instance, if you change windows, the council must be informed to explain what is going to be done and whether the change can be exempt or drawings need to be submitted. Especially when replacing windows, the current regulations must be met to comply with energy efficiency as well as structural and safety performance.”

Does your local council apply the NBR as they should apply it? According to Nick, not enough is being done because of the way the law is set up with the onus being on the homeowner to report whilst institutions such as bond holders, insurance companies and local authorities lack the resources or incentive to implement.

3. Homeowners not knowing about regulations and contractors not advising homeowners of their responsibility

Homeowners are not always aware of the law (NBR) and therefore not going to meet the regulations if they are not advised by contractors of their responsibilities.

Contractors should, ethically, point it out, even if it isn’t in their remit to do so.

Embassy Towers Sandhurst, GLA and Associates

Often contractors are also unaware of the regulations that must be applied, or they simply don’t inform homeowners.

Ignorance of the law is not an excuse. Go to the industry Associations such as AAAMSA and SAGGA for training and online published documentation on these requirements, and for more in depth training apply to SAGI

Withstanding of loads:

Let’s take the example of a glass pool balustrade. It’s a good example because it is likely a renovation or additional project, a beneficiation adding safety. But it may end up being inherently dangerous if it can’t stand up to the job.

Glass is a popular choice around pools because it doesn’t break the view, but importantly, the slab around the pool must be sufficiently strong to take the loads that the glass balustrading must, in terms of the NBR, resist, such as a child or adult falling against it.

The installation may look aesthetically pleasing, but may not necessarily be strong enough to hold the loads.

Contractors must know and apply the regulations. Glass must be able to withstand the wind load, line load, point load (100kg) and impact load, so that should people fall against it, they won’t hurt themselves. And then documentation from a competent person must be submitted by the contractor to the homeowner.

Homeowners must then forward the approval documentation to the council – but either due to ignorance or not being informed, this not always happens.

This then becomes a “victimless” crime. A non-conforming barrier is likely to be cheaper. But the “crime” happens when someone is injured or the glass falls over.

Consequences of not knowing the regulations

There are severe consequences to ignorance of the law. These include:

  1. Homeowners are probably not covered by public liability insurance. Think guests and children at a party, domestic workers, contractors. The homeowner can be held liable if a wrongful death occurs due to not adhering to regulations and not being compliant
  2. Homeowners insurance claims can be denied if there is not a valid certificate of occupancy – for example if part of a building has been added such as a pool balustrade or a door is changed for a frameless glass door and is not reflected in council records.
  3. The building inspector can deny the transfer of home ownership, so you can’t sell the house.
  4. Serious accidents can occur when someone falls into the pool, or the balustrade panel and systems aren’t correct because it is not compliant.

When balustrade systems are not compliant, glass cannot withstand the loads and when you lean against it, it may collapse. The loading code (SANS 10160) is there to help you know how strong it needs to be.

Glass fixing is only as strong as the weakest spot

Exploding glass: not a fallacy

Nick recalls a balustrade exploding for no apparent reason at a job in Cape Town. “There is a certain amount of probability that glass may do it without the reason being confirmed.”

Competent persons and signing off of forms

The regulations clearly say that a rational design must be done if the building or part of a building is not covered by deemed to satisfy rules. Then have a structural engineer sign off on the structural design (Form 2 of SANS 10400 A), followed by the competent person i.e. a glass expert signing off the glazing using Form 3.

Form 4 is the final sign off completed by the structural engineer who collects the Form 3’s.

Where glazing has been installed incorrectly and not to spec, there are times a gap can be found between where a Form 3 is missing but Form 4 has been received and approved by council.

Designs other than those covered by deemed to satisfy rules include:

  1. External Glass in a building taller than 10 m
  2. Glass in a balustrade or glass barrier protecting a change in level of more than one metre
  3. Glass floors and roof lights
  4. Frameless glass clamped or bolted into a building apart from some shower doors
  5. windows in a swimming pool or pond.

To say it is safety glass, doesn’t mean it is safe. When a ton of glass falls on you, you may have serious injuries or be killed.

Just because it’s safety glass, doesn’t make it safe.
Definition of safety glass: Manufactured to minimise cutting and piercing injuries.

The Silos Hotel, V&A Waterfront

Factors in glazing influencing energy efficiency

Three factors must be kept in mind regarding energy efficiency:

  1. Sunshine (solar radiation): Especially in South Africa, a country with a lot of sunshine and high solar radiation. Up to 1kW through a roof light and up to 700 watts per square metre. Think about how much a kWhr of electricity costs and multiply that by daylight hours per year to see the potential costs. It lets in a lot of light and heat.
  2. Conduction and insulation value: Heat loss or gained because of temperature difference. Double glazing and thermally improved frames can reduce this conduction to less than a quarter of single glazed aluminium frames. Double glazing also reduces condensation – a particular problem in the Cape winter rainfall areas. But when a building has double-glazing it is not a silver bullet particularly if it faces west, it cannot keep the heat out unless there is sufficient shading protecting or incorporated within the glass. When badly designed an air-conditioning system simply cannot handle that amount of heat to cool down the room.
  3. Leakage rates: Doors/windows must adhere to NBR to prevent air and water leaks. Air leaks destroy indoor comfort. Glazing regulations do not allow water to penetrate the building via windows which causes mould formation and surface and structural damage.

By law NBR, 10400 XA and 10400 N, the house must get an air-infiltration certificates for each window and door system installed, but enforcement is patchy and not all contractors are compliant or issuing. For a list of contractors and their systems that are compliant visit https://aaamsa.co.za/docs/AAAMSA-Contractors.pdf.

Coatings and performance glass

Fancy having windows made of silver? Silver coatings on glass is not only completely transparent but helps to keep the house warm in winter and cool in summer. Silver coatings can only be used in double-glazing and can then create an insulation coating that is transparent, allowing the same light as your car windscreen, into the room but keeping more than 60% direct radiation heat out. Whilst upping insulation by four times

When you put in big windows, make sure they can do what they are supposed to do and keep to the regulations.

Notes to specifiers regarding problems

In the way the industry is set up, the architect will make a drawing with the window schedule and give it to the main contractor to subcontract. It is essential to prioritise and to include a glass specialist on the project to ensure that the correct glass (and windows that do not leak water and air) is specified

Payback calculation and period

Regulations are there to be adhered to: The main contractor, developer, architect and all professionals on the project must follow the correct procedures and installations to prevent structural problems.

For instance, when you are building a home for long term, low cost of use, rather install good windows than the cheapest on the market. Cheap windows may lead to issues such as condensation and leaks, which will influence your payback calculation. Keep the payback period in mind and try to understand the numbers.

Factual information that is correct and unbiased about cost savings

  • Cost savings must be considered, especially with the rising cost of energy. One way is via energy efficiency and savings by using the correct window system and glazing and the correct installation. This way a massive 30% can be saved on energy. Homeowners can calculate the payback period when they decide on the ideal type of glass that they want to be installed, thus reducing air-conditioning and heating needs and saving significantly on the use of energy.
  • Structural and energy problems in buildings can decrease the value of the building and lead to unnecessary expenses. By having mechanical engineers as part of the professional team, they can assist in energy usage predictions and the correct choices up front.
  • Prediction model: The running efficiency of the buildings – studying the correct temperature per square metre per floor area in terms of external temperatures – can help you to decide on the ideal glass. Performances between glass vary and there are many glazing systems and shading elements available on the market. A contributing factor is to stop energy from getting to windows. External movable aluminium louvers or automatic blind systems can be installed.
  • If it is done right – the right glass and windows can lead to a four-year payback period, and you have high-performance glass for a design life of 30 years.
  • Assumptions made – Nov 2022, Electricity at R2.888/kW.hr
  • Even with a 930 % increase in glass price the payback is calculated at 4,2 years!

Maintenance regime

Would you maintain a vehicle ignoring the manufacturer? So why do we do this for glass windows and doors?

Windows and balustrades must be serviced and maintained by using the correct cleaning materials, regularly. property and homeowners often don’t maintain glazed systems and the structural elements are not maintained. There must be planned maintenance systems according to the installer’s instructions for longevity and prevent a failure of the system.

Calling in a glazing expert can ultimately save you money, save energy and reduce your legal risk significantly on commercial as well as residential buildings.

The issue: Dangerous and illegal glazing installations.

The solution: Understanding the risks, but also the value and payback of using correct glazing.

Spec tip: Contact a glazing specialist to help with compliance and cost saving calculations.

For more information, please contact Nick Wright:
Tel/WhatsApp: 0828081452
Email: nicholasrw@mweb.co.za

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