DP955^®

DP955® Performance

DP955® is designed not only to be stronger than traditional profiles but also more cost effective and faster to install. Its design provides stronger ribs to protect against buckling and a wide style pan to allow for safe foot placement.

With a wider cover width of 955mm, fewer DP955® sheets are required to be installed, saving both time and money. DP955®’s original look creates a distinctive and diverse design unlike traditional profiles ensuring a unique finish.

Sheet Tolerances
Sheet width: ±5mm
Sheet length: +10mm, –0mm. For horizontal wall cladding where notified at time of order of intended use, tighter tolerances
can be achieved +3mm, –0mm.

Roll-forming facility at: Auckland and Christchurch

Sheet lengths: DP955® 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.

Refer Section 2.1.3.4 of Technical Manual for more.

DP955® Limit State Load / Span Capacity

(span in mm, distributed serviceability loads in kPa)

Notes

1. In any category, spans above the maximum shown should not be used. Category 1 and 2 maximum spans are based on static point load testing as a guide, and
   further limited by practical experience of roof performance under dynamic foot traffic loads. Category 3 maximum spans are limited as a guide to achieving
   satisfactory appearance for wall cladding.
2. Loads given are based on 3 screw fasteners/sheet/purlin with load spreading washers.
3. Loads given are limited to a maximum of 4.5 kPa. 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 of the internal span
5. Design Criteria for Limit State Capacities
   1. Serviceability Limit State
      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.
6. System Design
   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. The capacities given do not apply for cyclone wind conditions.
   
   Serviceability Requirements
   While these categories are given for design guidance to meet the serviceability limit state criteria, foot traffic point load damage may still occur if there is careless placement of these point loads.
   
   Unrestricted-access roof
   Expect regular foot traffic to access the roof for maintenance work and able to walk anywhere on the roof. No congregation of foot traffic expected.
   Restricted-access roof
   Expect occasional foot traffic educated to walk only on the purlin lines, in the profile pans, or carefully across two profile ribs. Walkways installed where regular traffic is expected, and “Restricted Access” signs placed at access points.
   Non-access roof or wall
   Walls or roofs where no foot traffic access is possible or permitted. If necessary, “No Roof Access” signs used.
   
   
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.

Fastener Design

DP955® should be screw fixed to either timber or steel purlins. The use of the appropriate length of 12g or 14g screw will ensure failure by screw pull out will not occur under loads within the scope of the Limit State Load / Span Capacity Chart.

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

The Limit State Load / Span Capacity Chart is based on 3 screw fasteners/sheet/purlin with the use of load spreading washers and 36mm dia EPDM seals.

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 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 the Technical Manual.
3. Wherever the designer wishes to ensure the risk of fastener over-tightening will not cause dishing of the crest of the profile rib.

Where screws are used without load spreading washers, the profile’s load span ability is reduced by 60%. Long spans above 1.5m for 0.4mm and 2.0m for 0.55mm require the specification and use of side lap stitching screws – see Section 2.3.2C Installation Information: Layout and Fastening Technical Manual.

Design Example

Restricted access roof, 0.55mm G550 steel DP955® has a maximum end span of 2700mm and a maximum internal span of 4000mm.

The following distributed load capacities apply.

Fastener Layout Options

Product Brochure

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