Gas Hot Water Safety Rules Tighten After Wellington Apartment Block Incident

New gas hot water safety regulations require stricter installation standards and annual inspections following recent incidents in Wellington’s rental market. Property owners face immediate compliance deadlines for existing systems.

Installation clearance requirements

Gas hot water systems must maintain specific clearances from combustible materials and building elements. Continuous flow units require 600mm clearance above the appliance and 150mm on each side. Storage cylinder installations need 300mm clearance from walls and 450mm overhead access for maintenance.

Outdoor installations must be positioned at least 1000mm from windows, doors, or air intake vents. The appliance cannot be installed directly below eaves or overhangs that restrict natural ventilation flow.

Note: These clearances apply to both new installations and relocated existing units.

Ventilation and flue requirements

All gas hot water appliances require adequate combustion air supply and safe flue gas removal. Indoor units must connect to a certified flue system meeting AS/NZS 5601.1 standards. The flue terminal must project at least 600mm above the roofline and 300mm horizontally from any opening.

Natural draught systems need unrestricted air supply through permanent openings. A continuous flow unit rated at 26 litres per minute requires minimum 200cm² of free air area per opening, with openings positioned within 300mm of floor and ceiling levels.

• Balanced flue systems for confined spaces
• Power flue systems for challenging installations
• Conventional flue with adequate room ventilation

For example: A bathroom installation of a 16L/min continuous flow gas unit requires 150cm² ventilation openings plus certified flue connection to external air.

Gas supply and connection standards

Gas supply lines must be sized according to appliance demand and pipe run length. A 26 litre per minute unit typically requires 20mm copper tubing for runs up to 10 metres, increasing to 25mm for longer distances or multiple appliances.

The gas isolation valve must be located within 2 metres of the appliance and remain accessible for emergency shutdown. All connections require approved fittings and testing to 1.5 times working pressure before commissioning.

According to Building.govt.nz, building consent is required for gas hot water installations involving new gas supply lines or structural modifications.

Note: Only licensed gasfitters can install, modify, or disconnect gas appliances and supply lines.

Temperature and pressure control

Gas hot water systems must deliver water no hotter than 55°C at tap outlets in residential bathrooms and 45°C in early childhood facilities. Continuous flow units require internal temperature limiting controls or external thermostatic mixing valves (TMVs).

System pressure must not exceed 850 kPa. Installations on mains pressure supplies over 500 kPa need pressure reducing valves set to maximum 350 kPa for optimal appliance operation and longevity.

Relief valve discharge must connect to approved drainage meeting AS/NZS 3500.1 standards. The relief line cannot discharge where people might be scalded or property damaged.

For example: A rental property’s gas continuous flow unit must include a TMV delivering 50°C maximum to bathroom outlets, with the relief valve piped to external discharge point.

Inspection and maintenance obligations

Landlords must arrange annual gas appliance safety inspections by licensed gasfitters. The inspection covers appliance condition, flue integrity, ventilation adequacy, and gas leak testing.

Inspection records must be retained for five years and made available to tenants and regulatory authorities. Any identified defects require immediate rectification before continued use.

Property managers cannot ignore tenant reports of gas odours, pilot light problems, or incomplete combustion symptoms like sooting or yellow flames.

Note: Insurance policies may require current gas safety certificates for claims involving gas appliances.

Emergency shutdown procedures

Every gas hot water installation requires clearly marked emergency procedures posted near the appliance. The gas isolation valve location must be identified with permanent signage visible in emergency lighting conditions.

Tenants need instruction on recognising gas leaks, carbon monoxide symptoms, and appropriate emergency responses. This includes immediate appliance shutdown, area ventilation, and emergency service contact.

Carbon monoxide detectors should be installed in enclosed spaces containing gas appliances, though not mandated by current building code requirements.

How to comply

• Engage licensed gasfitter for installation design meeting AS/NZS 5601.1 clearance and ventilation requirements
• Obtain building consent for new gas supply lines or structural modifications to accommodate appliance placement
• Install temperature limiting controls delivering maximum 55°C to bathroom outlets and 45°C in childcare facilities
• Arrange annual safety inspections by qualified gasfitter with records retained for five-year minimum period
• Post emergency shutdown procedures and gas isolation valve location signage visible to occupants