• Dimond Structural Purlin Systems are intended for use as structural support to roofing and wall cladding. The systems provide for bolted connections to primary structural framework and include Dimond Structural DHS Purlins, Fastbrace, Bolted Brace
• Channels and Top Notch Purlins. The systems are subject to limitations on the environment in which they are used, depending on the type of coating specified.
• It is critical to product performance that the loads applied, member spans, member sizes and bracing points are designed within the appropriate Limit State Loads and limitations published in the Purlin Systems Design Manual
• Before commencing a project using a Dimond Structural Purlin System, the designer must ensure relevant information is available to the end user. Failure to observe this information may result in a significant reduction in product performance.
• Dimond Structural accepts no liability whatsoever for products which are used otherwise than in accordance with these recommendations.

The use of galvanised steel purlin systems should be avoided:

• In areas where high concentrations of chemicals are combined with a high humidity, where the system remains wet for long periods of time, causing rapid consumption of the galvanised zinc coating and eventual red rusting of the base metal for example, swimming pool roofs.
• Where the galvanised surface is being exposed to continuous moisture, without a chance for the surface to dry out for example, water tank roofs.
• In or near marine environments, where the prevailing wind carries marine salts which deposit on the purlin system, causing rapid consumption of the galvanised zinc coating and eventual red rusting of the base metal.
• In areas surrounding chemical or industrial storage buildings where any chemical attack may lessen the life of the structure or wind-driven chemical fumes may attack the galvanised coating.
• When in contact with or laid directly on ground.
• When in contact with timber and especially treated timber such as CCA (copper chrome arsenic) without the use of an isolating material such as DPC between the timber and purlin system.
• When used as supporting members to which fall arrest anchor points are attached.
• Where used as ceiling support members, vertical studs or horizontal wall girts where plaster board is fixed directly to the
  DHS purlin and a level 4 finish or above is required (fixing to a secondary adjustable grid framing system connected to the
  DHS purlins prior to lining with plasterboard will ensure tighter alignment and fixing tolerance, to achieve the required finish).
• When used in sub-floor areas with less than 450mm ground clearance.
• When used in sub-floor areas where ventilation does not comply with NZS 3604 Clause 6.14.
• Where embedded in concrete or where used within 50mm of the concrete ground slab.

Past history of use of Dimond Purlin Systems indicate that provided the product use and maintenance is in line with the guidelines in the Purlin Systems Design Manual, Dimond Purlin Systems can reasonably be expected to meet the performance criteria in clause B1 Structure and B2 Durability of the New Zealand Building Code for a period of not less than 50 years.