4.1 When choosing a thermal insulation product or combination of products, physical, chemical and mechanical properties and the significance of those properties should be considered. ASTM test methods are usually performed under laboratory conditions and may not accurately represent field conditions depending on process temperature, environment, and operating conditions. Performance results obtained using ASTM test methods can be used to determine compliance of materials to specifications but do not necessarily predict installed performance. Values stated in the ASTM material standards are those that apply to the majority of materials and not to any specific product; other tested values may exist for specific material applications.

4.2 Design of thermal insulation systems requires the understanding of process requirements, temperature control, heat loss criteria, control of thermal shock, and mechanical forces on insulation generated by thermal gradients and wind environmental conditions. Sometimes, the mechanical design of piping and equipment needs to be modified to support insulation adequately and provide for insulation weatherproofing. Process requirements may dictate the control of critical temperature to prevent freezing, maintain viscosity, or minimize internal corrosion. When handling heat transfer fluids such as ethylene oxide or hot oils, the selection of insulation materials and the insulation system design becomes critical. whereby If these fluids are absorb in insulation materials, the fluid flash point could be below the fluid operating temperature. Specified heat gain or heat loss and acceptable surface temperatures could also dictate thermal design of insulation systems. Environmental corrosivity, high wind, and extreme ambient temperatures affect the selection of weatherproofing and methods of its securement. A combination of these factors plays a significant role in the selection of insulation materials and application methods to provide long-lasting trouble-free service.

4.3 Application methods are generally defined by the purchaser's specifications. However, some specialty insulation systems, such as prefabricated insulation panels for ductwork, precipitators, and tanks, will also have supplemental installation requirements specified by the insulation system manufacturer. defined by the specification of the manufacturer.

4.4 In any application of thermal insulation, the insulation requires protection of some type, be it protection from the elements such as rain, snow, sleet, wind, ultraviolet solar radiation, protection from external forces that can cause mechanical damage, vapor passage, fire, chemical attack, or any combination of these. This protection can be provided in by metal, plastic, coated or laminated composites or both, mastic coatings, or a combination of the above depending upon the application, service, and economic requirements. Considering the enormous overall cost of a new facility, and comparing the initial cost of the insulated portion as a small percentage of that overall cost with the substantially increased operating cost as a result of inefficient insulation protection, it is common sense to provide only the best insulation system available and the best protection for that long-term investment consistent with the appropriate design and economic requirements. Usually a new facility is very expensive and the initial cost of the insulation portion is a small percentage of that overall cost. However, increased operating costs can result from inefficient protection.

4.5 Bid invitations should contain information necessary to determine how guarantees of materials and application will be resolved.

4.6 It is recommended that the purchaser provide a quality assurance program that defines the inspection of all materials, material safety data sheets (MSDS), and specific application procedures before and during progress of the insulation work.

4.7 During contract negotiations, the contractor and purchaser should discuss and agree to the procedures to be adopted for suitable periodic inspection and maintenance of the insulation systems to ensure that the initial performance of the material will be maintained. And, where applicable, they should agree to the methods of repair and replacement to be adopted in case damage occurs during service or overhaul.

1.1 This guide covers information on selection of insulation materials, systems design, application methods, protective coverings, guarantees, inspection, testing, and maintenance of thermal insulation primarily for industrial applications in a temperature range of -320 to 1200°F (-195.5 to 648.8°C).

1.2 This guide is intended to provide practical guidelines, by applying acceptable current practice while indicating the basic principles by which new materials can be assessed and adapted for use under widely differing conditions. Design engineers, the general contractors, the fabricators, and the insulation contractors will find this guide helpful.

1.3 Although some insulation system designs can serve as fire protection, this guide does not address the criteria specific to that need. API 521 Guide for Pressure-Relieving and Depressuring Systems is recommended as a reference for fire protection. This guide will however address the fire properties of insulation materials.

1.4 This guide is not intended for commercial, architectural, acoustical, marine, vehicle transport, or military use.

1.5 This guide does not address insulation system design for refractory linings or cold boxes whereby these are typically package units and of a proprietary insulation design.

1.6 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.

1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.