The responsibilities of a building owner are not straightforward. Subject to change and only ever seeming to become more onerous and strict, it can be hard to keep up. A case in point is the Healthy Homes Standards introduced on 1 July 2019. This sets forth a number of compliance changes through to July 2024, including alterations to ventilation requirements. So what does it all mean and what are your responsibilities as a building owner?
Much of a building owner's responsibilities are enshrined within the Building Act 2004. This sets out the rules every building in NZ must meet. It’s the primary legislation of the building industry and is there to ensure people’s health and wellbeing.
Underneath the Building Act sits the Building Code. This is the secondary piece of legislation and it outlines all of the minimum requirements. The code sets some pretty clear expectations for structural liability, durability, fire protection, energy efficiency and moisture control. As a building owner, your building won’t be awarded a consent unless it meets the performance criteria detailed in the code. And even if you don’t require a consent, you still need to meet the requirements of the Building Code.
Within that code are 3 general clauses and 38 technical clauses. It’s within each of these technical clauses you get the real detail, as it explains the objective of the clause, the functional requirements needed to meet that objective…and the performance criteria the building needs to meet. Flipping it around, if you meet the performance criteria then you satisfy the functional requirements which meets the objectives. It likely sounds more complicated than it is. Well, sometimes anyway.
The bit we’re really interested in is Clause G4 Ventilation. Its overriding objective is to safeguard people from illness or loss of amenity (essentially any reduction in physical or mental capacity) due to the lack of fresh air.
The functional requirement states that “spaces within buildings shall be provided with adequate ventilation consistent with their maximum occupancy and their intended use”. Importantly, and increasingly so since the onset of covid is this; “mechanical air-handling systems shall be constructed and maintained in a manner that prevents harmful bacteria, pathogens and allergens from multiplying within them”. In other words, as a building owner you need to make sure the ventilation is good enough for occupants and keeps them free from any risk of the ventilation throwing some airborne nasties at them.
Buildings must also have a means of collecting, or otherwise removing, a list of products from the spaces in which they are generated. Much of this might be common sense but it’s still needed. For example, the building (which really means ventilation in this context) must be able to deal with cooking fumes and odours, moisture from laundering, utensil washing, bathing and showering. Ventilating a bathroom is more complicated than it appears and in our opinion you’ll leave both the building structure and occupants at risk if you aim to only meet the code requirements for the bathroom. You can read more on our reasoning for this view here.
Other ‘products’ that need to be removed include; odours from sanitary and waste storage spaces, gaseous by-products and excessive moisture from commercial or industrial processes, poisonous fumes and gases, flammable fumes and gases, and the products of combustion.
Importantly, the Code specifies “the quantities of air supplied for ventilation shall meet the additional demands of any fixed combustion appliances''. A fixed combustion appliance is anything that burns fuel for heating, cooking or decorative purposes. So this covers the likes of space heaters, ranges, ovens, stoves, furnaces, fireplaces, water heaters and clothes dryers.
This all makes sense. Buildings need to be ventilated to stop them from deteriorating and to keep the occupants healthy and free from harm. The code simply puts common sense into legislation and makes sure we abide by that common sense.
Where it starts to get a little tricker, and where ventilation experts can be of a specific benefit, is in how you meet these functional requirements. It’s not simply a case of making sure there is ventilation. That would be entirely too subjective and there needs to be a quantifiable performance standard which defines what is considered acceptable (or otherwise).
The performance criteria for ventilation varies depending on the building size, number of occupants, the type of room needing ventilation and the use of that room. In general terms, as a building owner you need to ensure there is an adequate ventilation rate for the specific area. That is, enough of the outdoor air is brought inside to meet the prescribed number of air changes required. The indoor air purity also has to be at a specified level. This is mostly for workplaces and commercial buildings, where the level of contaminants in the air cannot exceed the limits recommended in workplace exposure standards and biological exposure indices.
The acceptable ventilation solutions within the Code are either natural, mechanical, or a combination of both. How to combine them for maximum effect is another example of how a ventilation specialist can help. There are specific requirements for the different types of ventilation solutions that they have to meet. For example, mechanical ventilation has to comply with a number of quality standards as defined by Standards New Zealand. So not any internet purchased unit will meet code. This really is where complexity comes in.
For residential building owners, responsibilities were increased with the passing of the Healthy Homes Standards on 1 July 2019. This was enacted to provide healthier homes for tennents and to improve the overall quality of NZ’s rental stock. The Government research showed too many homes were unacceptable, with dangerous levels of dampness and mould being one of the primary concerns as it affected the health of occupants.
The ventilation standards in particular, were seen as a way to combat the issues of mould and dampness. So it became the building owners responsibility to ensure their rental homes have openable windows in the living room, dining room, kitchens and bedrooms. Kitchens and bedrooms must also have extractor fans. The windows must be at least 5% of the floor area of the room they are in, and must be able to remain open in a fixed position. So this could be a louvre window. For kitchens, any new fans or rangehood need an exhaust capacity of at least 50 litres per second. For the bathroom, the capacity has to be at least 25 litres per second.
The Healthy Homes Standards need to be met for any private rental tenancy (new or renewed) after 1 July 2021. All private rentals must comply by 1 July 2024.
Covid has played its part in increasing the focus on ventilation also and building owners responsibilities may change as a result of this. For example, the Ministry of Education has already begun looking at ventilation in Early Childhood Education. There’s an increased emphasis on adequate ventilation and we only see this increasing in the short to medium term.
What does it mean for a building owner? It may have an effect on your ability to attract tenants and what price you can charge. As ventilation becomes more important, a building with demonstrably good ventilation may be seen more favourably. It also means there’s a degree of safeguarding which may be necessary. Ventilation which goes beyond the current requirements will provide this, so any future mandates may be (possibly) met.
In short, it’s all getting more complicated and an increasing number of buildings will need remedial works, whilst new builds have an opportunity to future proof themselves. The level of complexity is increasing and identifying a solution to meet the heightened scrutiny is getting tougher. This is where engaging a ventilation specialist really helps. We know not only what is required but can make some educated assumptions of what might be required in the future.
If you have any questions or would like to discuss ventilation requirements for your building, please get in contact. We look forward to speaking with you.
