If you don’t, seismic restrains are an excellent choice when installing your cylinder.
What are seismic restraints? Seismic restraints for hot water cylinders are steel straps used to keep a hot water cylinder in place, preventing it from falling during an earthquake. They are affixed by screwes and washers of a certain standard to the wall framing around the cylinder. Hot water cylinders are heavy items, with a 135 litre cylinder weighing around 170 kg when it’s full of water. If there are no restrains, this is quite a lot of weight to be flung around in an earthquake, not to mention if you have an even bigger one. It can also damage other items such as pipes which are connected to it, and cause a flood.
Along with this, NZBC B1.3.2 standard requires building elements (including storage water heaters) to be adequately supported including support against earthquake forces. The method illustrated in Figure 14 is acceptable for water heaters up to 360 litre capacity. Where fittings and pipework are attached to the water heater through the supporting platform or floor a 50 mm minimum clearance shall be provided between the fitting and the support structure. 6.11.5 An alternative acceptable solution for securing storage water heaters against seismic forces is given in Section 203 of NZS 4603.
If you are getting a new cylinder installed, make sure that it comes with a seismic retraint kit!
Retrofitting a seismic restraint kit
If you already have your cylinder installed and are not looking to replace it anytime soon, it is possible to retrofit seismic restraints to your exisiting cylinder. However, this is more complicated than installing with a new cylinder, since access behind the cylinder is required. If this is something you would like to do, it is best to contact us to discuss the job.
A customer recently called us with the issue of their low pressure cylinder finally giving up on them. They needed a solution for hot water and decided that mains pressure would be the ideal thing to go for. So we recommended going for a Rheem 180L mains pressure cylinder to provide them with the solution they were looking for.
We sent our plumber off with a new Rheem 180L mains pressure cylinder to replace the old Simplex unit and provide the customer with higher pressure hot water in their home. These hot water cylinders are extremely popular upgrades for old low pressure systems because they are easy to install, provide reliable mains pressure hot water, are very efficient and last for years to come.
While there, our plumber was also asked to replace an old faulty Wastemaster with a new Hurricane unit that do an even better job of chopping up the scraps.
“IMPORTANT NOTICE: Safe trays are now compulsory with all new internal hot water cylinder installations, as per G12/AS1 clause 5.2.3 of the New Zealand building code.”
The above notice is what you will find on most newly sold (Image of a Rheem) hot water cylinders. Last year one of our blog posts discussed whether or not you need a cylinder tray. At the time the blog discussed a faulty product which resulted in flooding and insurance claim. In that particular instance the damage was minimal and covered by the manufacturer. Can you imagine the yearly claims when thousands of hot water cylinders are installed without hot water cylinder trays?
You can take a big guess on who would have lobbied the idea and pressed to get this incorporated into recent New Zealand building code G12 amendments. This standard sets a legal guideline on how a hot water cylinder may and may not be installed.
Looking across the ditch, our Australian friends have had this requirement (regulation) as part of their compliance documents (e.g standard AS/NZS 3500) since 1996 but for some reason it never made it into the New Zealand building code, until now.
AS/NZS 3500 is also an acceptable standard in NZ which begs the question, why bother with two sets of standards in the first place?
Previously, accidental discharge control was optional unless a potential risk of water damage to another property existed, which in most cases only really applied to multi-story situations. Although control was considered “good practice” the homeowner could “opt out” to achieve savings on the installation. Or the plumber would keep it on the quite “to be competitive” and win a job against more expensive quotes that included the installation of a hot water cylinder tray.
Before the change, manufacturers such as Rheem have stated in installation instructions that a safe tray must be fitted, meaning plumbers should have already been recommending, quoting and installing hot water cylinder trays.
Now that this law has come into effect, ignorance is no longer bliss and benefits are relative to:
> The manufacturer knowing that installers can made responsible for water damage if the standard is not followed.
> The homeowner, knowing that any potential leaks are controlled while they are sleeping.
> The insurance, knowing they can legally peruse compensation on behalf of the homeowner.
Additional benefits also include:
Level playing field when plumbers are pricing jobs.
Prevention being the best protection.
NOTE: Plumbers and homeowners should ensure the installation complies with the updated standard to avoid any costs associated with non-compliance or resultant damage from water discharging from a hot water cylinder.
SOME CHALLENGES AND CONSIDERATIONS
Progress is always accompanied with challenges and challenges are accompanied with questions.
Some legalities are still undefined and It is not clear on whether a cylinder try must be installed on replacement hot water cylinders as well as newly installed hot water cylinders. When a “repair” or “like for like replacement” takes place, the building act allows one to maintain the current state of affairs. For example, although tempering valves are required by law, a plumber does not have to install a new one when replacing an existing old or damaged hot water cylinder that never had a tempering valve to begin with. Its good practice but not a legal requirement. He can just go ahead and maintain the existing setup treating the installation as a “like for like” situation.
But then this principal does not apply to seismic restrains. The DHB is yet to comment on this and we will update the blog once we know more.
Because compliance is relative and no job is like another, you want to be safe and ask the right questions before committing to any installation. Its always best to make an educated decision rather than deal with the unwanted consequences of ignorance.
ALTERNATIVES WHEN IT GETS TO EXPEN$IVE!
A cylinder tray needs to be connected to an approved point of discharge via a 32mm – 40mm drain. In many cases, for example double story homes the route of this drain becomes a major challenge. Especially when you are talking about cutting walls open or having surface mounted pipework to get the drain out.
If the cost or convenience of having a cylinder tray is not attractive, there are alternatives within the same ballpark in terms of $$$.
For example Instant water heating. For about the same price of new hot water cylinder + tray you can convert to gas and enjoy the many benefits. We offer LPG and natural gas solutions. Future-proof or expand, your possibilities are limitless.
Relocate your hot water cylinder to the outside and free up that cupboard space. In external situations, no cylinder tray is required and the costs are about the same as a new internal hot water cylinder + tray.
Most of our customers tend to go for this option when the installation of a cylinder tray becomes too difficult or expensive. Talk to us for more information.
AMENDMENTS IN G12,
Lets have a look at G12 a bit closer.
You can view the old and newer version (third edition) of G12 by following this link VIEW G12 AMENDMENTS.
Its very interesting to see that they have removed the wording from 6.11.3
a) Safe trays complying with Paragraph 5.2.3 where water could penetrate another household unit within the same building.
Which now reads:
6.11.3 Storage water heaters shall have: a) Safe trays complying with Paragraph 5.2.3
The above relevant paragraphs read as follows:
5.2.3 now reads..
Safe trays Performance E3.3.2: states that; Free water from accidental overflow from sanitary fixtures or sanitary appliances must be disposed of in a way that avoids loss of amenity or damage to household units or other property. An acceptable method of preventing water damage is to locate a safe tray below the water tank (see Figure 4). The safe tray shall incorporate a drain with a minimum diameter of 40 mm. Where the tank overflow discharges into the safe tray, the diameter of the safe tray drain shall be greater than the overflow pipe from the tank and comply with Paragraph 5.2.2.
5.2.2 Overflow pipes Water tanks shall have an overflow pipe to discharge any overflow to a visible place within the same property that does not create a nuisance or damage to building elements. The overflow pipe shall be sized so that the discharge capacity is no less than the maximum inlet flow. The outlet of the overflow pipe shall not permit the entry of birds or vermin. Overflow from a WC cistern may discharge internally into a WC pan.
COMMENT: Manufacturers’ literature must be referenced for pressure and flow information on tempering valves and tapware. Outlets (e.g. shower mixers and showerheads) must be appropriate for the available flow and pressure. Note the limitations on lengths and pipe sizes given
6.11 Water heater installation
6.11.1 Water heaters shall be installed in accordance with the manufacturer’s instructions.
6.11.2 Where heating units, sacrificial anodes, thermostats, pipework connections, valves, or other accessories being components of a storage water heater are installed, they shall be accessible for inspection, maintenance and removal.
6.11.3 Storage water heaters shall have: a) Safe trays complying with Paragraph 5.2.3 b) Connections compatible with the pipe material used, and c) Drain pipes (for every storage water heater of more than 45 litres capacity) which: i) have a conveniently located isolating valve, and terminate with a cap or plug suitably located to easily empty the vessel for maintenance, or ii) terminate outside the building with a cap only.
The installation below shows the safety valves discharging into the cylinder plug and waste, which does not comply as one could argue that these pipes are blocking the passageway designed for the control of accidental water which is managed by the safe tray only. NZ Regulations define acceptable methods of discharge which includes safety valve drains.