This specification covers the general requirements, property and performance requirements, quality and inspection tests. An approved source list is included.

When no Grade is specified on the print, Grade 1 material will be provided.

If insulating performance is affected by orientation, the attachment side must be identified.

Restricted Chemical Substances

Effective JANUARY 1, 2007, all product supplied to the requirements of this specification must comply with the requirements of CEMS B-50.

APPLICATION

This material specification outlines the requirements for under hood acoustical insulation requiring high sound absorptive characteristics. The NAVISTAR Truck Development and Technology Center, Vehicle Acoustics Group must approve material supplied for acoustical applications. Various grades are specified for Type I and/or Type II requirements for certain thermal environments or operating conditions.

Grade 1 – Material is a composite blend of synthetic and natural fibers, recommended when under hood temperatures are above 275°F.

Grade 2 – Material is made from polyester fiber and is recommended when under hood temperatures are below 275°F.

Grade 3 – Material is made from polyether urethane acoustic foam, which may be composited with facing materials. It is recommended when under hood temperatures are below 225°F. Specially designed Grade 3 foam composites with facings may be used for under hood temperatures above 275°F as long as the composite does not come into direct contact with the heat source.

Grade 4 – Material is made from a combination of polypropylene micro fibers and polyester staple fibers. It is designed for use in environments where the operating temperature is less than 250°F.