Access the Code of Practice online

This registration will be required once-only per browser/device, which is achieved using a cookie stored on your device.

There is no password required, and your information will not be shared with any third parties.

Please register and accept the terms for the NZMRM online COP
By ticking this box you confirm that you have read and accept the Terms listed below


Although the information contained in this Code has been obtained from sources believed to be reliable, New Zealand Metal Roofing Manufacturers Inc. makes no warranties or representations of any kind (express or implied) regarding the accuracy, adequacy, currency or completeness of the information, or that it is suitable for the intended use.

Compliance with this Code does not guarantee immunity from breach of any statutory requirements, the New Zealand Building Code or relevant Standards. The final responsibility for the correct design and specification rests with the designer and for its satisfactory execution with the contractor.

While most data have been compiled from case histories, trade experience and testing, small changes in the environment can produce marked differences in performance. The decision to use a particular material, and in what manner, is made at your own risk. The use of a particular material and method may, therefore, need to be modified to its intended end use and environment.

New Zealand Metal Roofing Manufacturers Inc., its directors, officers or employees shall not be responsible for any direct, indirect or special loss or damage arising from, as a consequence of, use of or reliance upon any information contained in this Code.

New Zealand Metal Roofing Manufacturers Inc. expressly disclaims any liability which is based on or arises out of the information or any errors, omissions or misstatements.

If reprinted, reproduced or used in any form, the New Zealand Metal Roofing Manufacturers Inc. (NZMRM) should be acknowledged as the source of information.

You should always refer to the current online Code of Practicefor the most recent updates on information contained in this Code.


This Code of Practice provides requirements, information and guidelines, to the Building Consent Authorities, the Building Certifier, Specifier, Designer, Licensed Building Practitioner, Trade Trainee, Installer and the end user on the design, installation, performance, and transportation of all metal roof and wall cladding used in New Zealand.

The calculations and the details contained in this Code of Practice provide a means of complying with the performance provisions of the NZBC and the requirements of the Health and Safety at Work Act 2015.

The scope of this document includes all buildings covered by NZS 3604, AS/NZS 1170 and those designed and built under specific engineering design.

It has been written and compiled from proven performance and cites a standard of acceptable practice agreed between manufacturers and roofing contractors.

The drawings and requirements contained in this Code illustrate acceptable trade practice, but recommended or better trade practice is also quoted as being a preferred alternative.

Because the environment and wind categories vary throughout New Zealand, acceptable trade practice must be altered accordingly; in severe environments and high wind design load categories, the requirements of the NZBC will only be met by using specific detailing as described in this Code.

The purpose of this Code of Practice is to present both Acceptable Trade Practice and Recommended Trade Practice, in a user-friendly format to ensure that the roof and wall cladding, flashings, drainage accessories, and fastenings will:

  • comply with the requirements of B1, B2, E1 E2 and E3 of the NZBC;
  • comply with the design loading requirements of AS/NZS 1170 and NZS 3604 and with AS/NZS 1562;
  • have and optimised lifespan; and
  • be weathertight.

COP v24.03:Useful-Information; Velocities

18.6 Velocities 


18.6A Velocity

mile / hour


Velocity is the distance travelled in one second (m/s).

The following speeds are approximate and are assumed to be constant and in a straight direction and therefore are also the velocity.

Description marked R are speed records.

18.6B Velocity Comparison

 m/skm/hmile/hourBeaufort Scale
Calm0<10 Smoke rises vertically
Light Air0.8321Smoke rises on angle
Man walking1.  
Light breeze2.595.62Feel wind on face
Gentle breeze4.516103Flags extend
Moderate breeze72515.54Raises dust
Fresh breeze1035225Trees sway, waves
Runner 100m R103522  
Strong breeze12.545286Telegraph wires whistle
Racehorse trotting R155433  
Moderate gale15.556357Difficult to walk
Fresh gale18.567428Branches break
Racehorse R196842.5  
Racing cyclist R227949  
Strong gale2382519Slight building damage
Whole gale26.5966010Trees uprooted
N.Z. Road speed limit2810062.5  
Skier downhill2810062.5  
Storm311116911Widespread damage
Low wind speed NZS 36043211571  
Hurricane33.51207512Severe damage
Medium wind speed NZS 36043713383  
High wind speed NZS 36044415898  
AS/NZS 117045162101  
Swift - fastest bird47169105  
Very high wind speed NZS 360450180111  
AS/NZS 1170 (Cook Strait)51184114  
Moderate cyclone55198153  
Tennis serve R66238148  
Bullet train (Japan)69248154  
Severe tropical cyclone70252157  
TGV express train77277172  
Wind R103371230  
Boeing 747256920572  
Sound in air3331199743  
Land speed R3411228763  
Rotation of earth at equator46516741040  
303 Bullet79228511772  
Lockheed Blackbird R98135292193  
Moon round the earth100036002237  
Sound through steel51001836011408  
To escape earth’s gravity78232816317500  
Fastest man has travelled111764023425000  
Earth round the sun2970010692066437  
Pioneer space probe66720240192149248  
Light and electric waves2993880001077614064669600000186,000 miles/sec