UL 1821

1.1 These requirements cover thermoplastic pipe and fittings for use in wet pipe sprinkler systems for fire protection service.

1.2 Thermoplastic pipe and fittings covered by these requirements are intended for use in sprinkler systems in any of the following types of occupancies:

1. Light hazard occupancies as defined in the Standard for Installation of Sprinkler Systems, NFPA 13;

2. Residential occupancies as defined in the Standard for Installation of Sprinkler Systems in One and Two Family Dwellings and Manufactured Homes, NFPA 13D; and

3. Residential occupancies as defined in the Standard for Installation of Sprinkler Systems in Residential Occupancies Up to and Including Four Stories in Height, NFPA 13R.

1.3 The pipe and fittings covered by these requirements are intended to be installed in accordance with the Standard for Sprinkler Systems in One and Two Family Dwellings and Manufactured Homes, NFPA 13D; the Standard for Sprinkler Systems in Residential Occupancies Up to and Including Four Stories in Height, NFPA 13R; or the Standard for Installation of Sprinkler Systems, NFPA 13.

1.4 A product that contains features, characteristics, components, materials, or systems new or different from those covered by the requirements in this standard, and that involves a risk of fire or of electric shock or injury to persons shall be evaluated using appropriate additional component and end-product requirements to maintain the level of safety as originally anticipated by the intent of this standard. A product whose features, characteristics, components, materials, or systems conflict with specific requirements or provisions of this standard does not comply with this standard. Revision of requirements shall be proposed and adopted in conformance with the methods employed for development, revision, and implementation of this standard.