How to avoid getting hot under the collar by understanding air-conditioning
Without a doubt Air Conditioning is the biggest cost pitfall in a building!
Commonly referred to as ‘Mechanical Services’ I have created this blog to help all the non-engineers understand what is involved in air-conditioning and what you need to know to save yourself money.
The ‘Need the Knows’ Hot List
First up, you need to know what these concepts mean:
- Fresh Air
- Temperature Control Cooling
- Base Building
- Splits + Condensers
- Fresh air, oxygen, the key to life. Sounds like the introduction to a David Attenborough series but in Workspace Design and Fitout it is the single most important factor but the most commonly ignored in creating a productive office.
Fresh air is delivered to office space at a common capacity rate of 1 per person per 10 square meters. This means if you have an office of 100sqm. It is designed to fit 10 people, air-wise.
As you know this probably works fine when it is just you and your staff. But oxygen also needs to be supplied to your boardroom of 35 square meters when you are holding a 15 person board meeting or a 10 person who-ha.
The supply of fresh air is affected when you exceed the capacity, which is why you need to supplement this. It’s important to business, not because your staff will die from a lack of oxygen, but well before then you will notice them become very unproductive and then literally fall asleep at their desk with oxygen deprivation.
- Temperature control is a completely different mechanism to the supply of Fresh Air. Fresh Air for example is a Building Code of Australia requirement, whether it is supplied at a comfortable 22 degree temperature is not.
Temperature control inside the building is measured with Thermostats which control the temperature in a particular Zone.
A common zone in most buildings is a Perimeter Zone, most likely divided up between each façade. This controls the temperature by, say on a hot day when the sun is belting in, the thermostats in that zone activate the cooling within the perimeter zone thus controlling temperature. This happens within all the Zones within your office space.
- Base Building system is the system the building provides. It will be compliant to achieve fresh air for 1 person per 10 square meters.
There are a range of variant technologies which I won’t bore you with but it is important to explain the basics of how the most common system works. Introducing – the common commercial suspended ceiling.
On the inside of the ceiling is concealed all the mechanical infrastructure. On the ceiling you will see ceiling registers or grilles blowing temperature controlled air. Generally in the same room you will also see an empty grille, seemingly doing nothing. If you look closer you will see it’s just a hole with nothing between it and the space above.
The ceiling register essentially is the instrument at the end of a series of ducts that is blowing the air. The empty grille is referred to as the return air grille. Its job is to suck up all the used air. It does this by having a different air pressure above the ceiling.
It is important to have a return air grille sucking in negative air and an air register providing positive air in every room. Once you have completed your fitout and all the infrastructure is in place around all the offices and rooms, the system then needs to be Balanced in order to achieve an even air pressure.
- Supplementary mechanical systems are required when you exceed the 1 in 10 rule. This means an engineer will design a “BCA compliant“ solution so you will be able to supply Fresh Air to an area currently lacking because of over-use.
Identified early, these solutions can be worked into the overall project, however, this is by far the largest single cost to a fitout. Most ‘over 1000 sqm offices’ require 2 – 3 supplementary units to deal with big board rooms, conference facilities, comms rooms, highly populated open plan workspaces and even after-hours air-conditioning.
Throughout my career, my team and I have been able to identify that this single item, supplementary air conditioning, costs between 1/6th to 1/10th of the overall value of the project value. A massive cost on a product you can’t even see.
- Split systems are those cassette units that you have in your home and sometimes in smaller offices. To clarify, these units are only for cooling/heating and do not provide any fresh air. Hence they are not suitable as a cheap solution for your office space.
These are known to be used in Comms Rooms as this is not a habitable area, however, also be warned that split systems are a domestic product and not meant to be used for 24/7 cooling.
Condensers are the units that provide the chill or heat via a condensed water line. For split systems, you see these rectangular boxes hanging from the side of buildings or terraces. The distance of these units to the split cannot exceed between 5 – 10 meters. On special commercial units you can achieve a bit more. This is important to understand as unless you are close to the roof of an office building, you will generally need to rule out this solution.
What can I do about all this?
Not being an engineer, you can’t investigate yourself but you can ask questions and if necessary, bring in an independent specialist to give you a professional evaluation of the mechanical systems in the space you are considering.
My 4 Tips that will you will love me for:
- Ensure that there is a quality mechanical system installed in the space you are considering. That it is regularly serviced and relatively new.
- Ask for specific details on the system so you take to someone who does know, for an opinion.
- To avoid the unnecessary cost of installing expensive supplementary systems, design the space to suit the air-conditioning. i.e., don’t plan to put 20 staff in work stations in an area, which is designed for fresh air for only 10.
- If this approach doesn’t work, then factor in the cost of supplementary air-con systems at the get go as an essential item in your fit-out budget to avoid any surprises further down the track.
Above all, we advise to get involved with your workplace design team as soon as you start thinking about moving offices. At AGERO Group, we work closely with our clients at these early stages to identify potential pitfalls and advise which spaces will work best for their requirements and budgets.
We invite you to speak with us, obligation-free, for more information on how our collaborative approach offers amazing solutions for our clients.
Want to avoid the big cost of keeping your cool?
Then please, contact AGERO Group for a no obligation conversation with our team
T 03 9646 7929