minimum tread depth nz

The minimum permitted tread depth is 280 mm but with ample space for the stairs 300 mm treads have been selected. Building Code compliance document D1AS1 does not specify a width for common or main private stairways the most common stairway applicable within residential buildings but recommends no less than 850 mm.

Tyre Safety Aa New Zealand

OSHA 191025d4 requires spiral stairs to have a minimum tread depth of 75 inches 19 cm measured at a point 12 inches 30 cm from the narrower edge.

. Multiply the tread depth by the number of treads to calculate the overall length of the stair. 300 13 3900 mm. For these the NZTA has retained the old requirement of at least 15mm tread depth across ¾ of the tread width and around the whole circumference of the tyre.

This requirement is based on tyre manufacturers recommendations for adequate performance in the snow. The legal minimum tread depth is 15mm in all the principal grooves around the entire circumference of the tyre. Virtually all tyres have moulded tread-depth indicators.

Or call us with your query on 0800 896 500. Most stairs are between 900mm 1100mm wide for comfortable use. However many agencies change their tyres at 3mm and we would recommend replacing your tyres at or before 2mm.

The rule now states that a tyre must have a tread pattern depth of at least 15 mm excluding any tie-bar or tread depth indicator strip within all principal grooves that contain moulded tread depth indicators and around the whole circumference of the tyre. If you can replace your tyres at 3mm of tread depth. There is a substantial drop in wet breaking performance under 3mm of tread depth.

The likelihood of an overstep decreases significantly with increasing tread depth. 300 13 3900 mm Each tread will also have a 20 mm projection giving a total tread depth of 320 mm but the projection does not add. The legal minimum in NZ and Australia is 15mm.

However a small number of tyres such as some retreaded or vintage tyres may not have moulded tread-depth indicators. The rule also introduces a new minimum tread depth for winter tyres of 4 mm. Tyre performance in wet weather deteriorates when tread depth is below 4 mm.

At least 16mm throughout a continuous band in the centre 34 of the tread and around the entire circumference of the tyre. Minimum Stair Tread Depth Chart. Treads that project past the riser by at least 15 mm but not more than 25 mm to prevent toes being caught while walking up stairs.

Multiply the tread depth by the number of treads to calculate the overall length of the stair. Legal thread depth or tyres. Some studies have shown that going from 3mm to 15mm results in a 25 reduction in wet weather braking performance.

According to the NZTA the legal minimum tread depth is 15mm but advisors say the grip of tyres in wet conditions reduces once the tread is below 3mm. These must be at least 15mm around the whole circumference of the tyre. So if your tyres are at an already dangerous but WOF passable tread depth and the time between WOF inspections has doubled it is fair to assume those who rely on the WOF to check tyre safety may very well find themselves driving below the legal minimum for a period of time.

The minimum legal tread depth is 15mm within all principal grooves that contain these moulded tread depth indicators. Virtually all tyres have moulded tread depth indicators. Tread-depth indicator or tread-wear indicator means the projections within the principal grooves designed to give a visual indication of the degree of wear of the tread.

Both requirements will be checked at entry inspection when a vehicle first enters New Zealand and at periodic warrant of fitness or certificate of fitness inspections. BRANZ Guideline February 2012 stair widths. To help locate these on a tyre inspectors should look for a or TWI mark on the outer edge of the tyre side wall most tyres have these marks.

15mm is the minimum tread depth required for car tyres to get a Warrant of Fitness. A tread depth of at least 275 mm. There is currently no specified minimum width in the Building Code.

In the UK it is 16mm. You can check current stair regulations in full here PDF. Analysis of stairway related accidents shows that overstepping of treads is a common cause of accidents.

Minimum permitted tread depth is 280 mm but with ample space for the stairs 300 mm treads have been selected. The minimum legal tread depth limit is 15 mm for car and van tyres. IBC 101110 requires spiral stairways to have a 6 34 inch 171mm minimum clear tread depth at a point 12 inches 305mm from the narrow edge.

Stair width of 9001100 mm. See how easy it is to check your tyre tread using a 20 cent coin. However wet weather performance drops off rapidly once tread depth is below 3mm.

Even step heights risers the riser height plus one tread depth should be in the 580 mm to 620 mm range. Megatyre Browns Bay North Shore Auckland. Principal grooves are the ones that have a tread depth indicator in them.

Adequate tread depth is essential for stairway safety. The legal minimum tyre tread depth varies by each type of vehicle. Treads that are all at the same width.

The minimum tread depth of 15mm in NZ is too low and there have been calls for it to be raised. There is always one more riser than treads so for 14 risers there will be 13 treads. At least 10mm throughout a continuous band across at least 34 of the breadth of the tread and around the entire circumference.

When designing stairs factors to consider are the design parameters given in D1AS1 for. Tyres must have a tread depth of 15 millimetres over three-quarters of the surface to pass a Warrant of Fitness. The wear bars show when you only have 15mm of tread left at which point your tyres are on their absolute minimum legal tread depth.

Another easy check is to insert a 20c coin into the tread. Of course while the legal minimum is 15mm the more tread you have the better grip your tyres will have and the safer you will be so it makes sense to check them regularly. In the wet or travelling at high speeds your grip and stopping distances are seriously compromised if you have below 15mm of tread.

Riser height and tread depth should be of a uniform height within a tolerance of 5mm in one flight. Most tyres have moulded tread-depth indicators which are flush with the tyre tread when it has reached the minimum depth. Every day mechanic Neville Hawker checks cars with dangerously bald tyres.

These are the thin flaps of rubber that sit crosswise in the groove and they are 15mm in height.

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