Six Rib

Six Rib Performance

Dimond Six Rib® offers clean lines and a strong visual appeal. Six Rib® is already suited for cladding applications down to 4 degrees. Distinguishes itself with its lower rib height giving it a lighter weight looking appearance.

Sheet Tolerances
Cover: ± 5mm - Sheet length: +10mm, -0mm (steel)
Cover: +10mm, -15mm – Sheet length: +0mm, -15mm (aluminium)

Roll-forming facility location: Invercargill

Crimp curving facility location: N/A

Manufacturing location for DuraClad®: N/A

Sheet lengths: Six-Rib® is custom run to order.

Where long sheets are used, consideration must be given to:

• Special transportation licences for sheet lengths over 25m
• Site access for special lifting equipment
• Fixing techniques to accommodate thermal expansion.

DIMOND SIX RIB® LIMIT STATE LOAD / SPAN CAPACITY CHART

(span in mm, distributed serviceability loads in kPa)

Notes

1. In Restricted Access Roof and Non-Access Roof & Wall applications, spans exceeding the maximum values shown should not be used. The maximum spans for Restricted Access Roofs are based on static point load testing as a guide and are further limited by practical experience of roof performance under dynamic foot traffic loads. For Non-Access Roof & Wall applications, the maximum spans are limited to ensure satisfactory appearance for wall cladding.

    

2. Loads given are based on 5 screw fasteners/sheet/purlin.

    

3. Loads given are limited to a maximum of 4.5kPa. If design requirements exceed this limit, Contact Dimond for specific advice.

    

4. End span capacities given in this table are based on the end span being 2:3 ratio of the internal span.

    

5. Design Criteria for Limit State Capacities
   1. Serviceability Limit State (SLS Design)
      No Deflection or permanent distortion that would cause unacceptable appearance, side lap leakage or water ponding, due to foot traffic point loads, inward or outward wind loads or snow loads.

   2. Ultimate Limit State (ULS Design)
      No pull through of fixings or fasteners withdrawal resulting in sheet detachment due to wind up-lift (outward) loads.

       

6. System Design
   The span capacity of Six Rib is determined from the Six Rib Limit State Load/Capacity Chart using the section of the chart appropriate to grade and type of material, and to the category of serviceability selected from the three categories below. Serviceability loads have been derived by test to the NZMRM testing procedures. To obtain an ultimate limit state load we recommend factoring the serviceability load up by 1.4 in-line with NZMRM guidelines.
   Note: The capacities given do not apply for cyclone wind conditions.
   
   Serviceability Requirements
   While these categories are provided for design guidance to meet the serviceability limit state criteria, foot traffic point load damage may still occur if point loads are placed carelessly.

   
   Service Category
   Refer to MRMCOP 3.7.4 Roof Traffic. The designer must consider the degree and type of foot traffic expected on a roof. The following requirements are subjective standards and must be considered in line with customer expectations, building use, and type. More robust design than specified below (such as reducing purlin spacing or adding protection from mechanical action) is required for roofs that are regularly accessed, used as staging by subsequent trades, or areas adjacent to access points, particularly step-down access
    

7. Wind Pressure Guide
   As a guide for non-specific design the following S.L.S. design loads in accordance with the MRM Roofing Code of Practice can be used for buildings less than 10m high, otherwise AS/NZS 1170.2 should be used
   Low wind zone = 0.68kPa, Medium wind zone = 0.93kPa, High wind zone = 1.32kPa, Very high wind zone = 1.72kPa and Extra high wind zone = 2.09kPa.

Six Rib Fastener Design

Fasteners that are used to secure Six Rib down as a roof cladding must penetrate into the purlin a minimum of 30mm for timber and 6mm for steel purlins. For wall cladding, the fasteners must be long enough to pass through the substrate, cavity batten and into the solid framing by 30mm for timber and 6mm for steel.

For screw size range and fastener/washer assembly refer to Section 2.2.3.1 of Technical Manual

The Limited State Load/Span Capacity Chart is on 5 screw fasteners/sheet/purlin without the use of load spreading.

Profiled metal washers are recommended for use;

1. On end spans, or large internal spans where the Ultimate Limit State distributed load is limiting. Contact Dimond Roofing for specific advice in these design cases.
2. When required to enable the fixing system to accommodate the thermal movement of long sheets – see Section 2.1.3.4 Thermal Movement of Technical Manual
   
3. Whenever the designer wishes to ensure the risk of fastener over-tightening will not cause dishing of the crest of the profile rib.

Use in serviceability categories (1) or (2) can allow the reduction of fasteners to an average of 3 screw fasteners/sheet/purlin. If this is done, the distributed load capacities given in the chart should be reduced using a multiplying factor of 0.6.
Long spans may require specification and use of side lap stitching screws – Section 2.3.2 C Installation Information: Layout and Fastenings of Technical Manual.

Design Examples

Restricted access roof, 0.55mm G550 steel Six Rib has a maximum end span of 1500mm and a maximum internal span of 2200mm. The following distributed load capacities apply.

Fastener Layout Options