America’s first national standard for retrofit roof drains, developed by SPRI in 2004, was re-approved by the American National Standards Institute (ANSI).
WALTHAM, Mass. - America’s first
national standard for retrofit roof drains, developed by SPRI in 2004, was
re-approved by the American National Standards Institute (ANSI). The revised
RD-1 standard was re-approved as required by ANSI’s policy that all National
Standards be re-evaluated every five years. The standard is designated
ANSI/SPRI RD-1, 2004, “Standard for Retrofit Roof Drains.”
SPRI, the association representing sheet membrane and component suppliers to
the commercial roofing industry, developed this roof drain standard to fill the
information void regarding retrofit drains.
“Retrofit drains that meet this standard have proven to perform at the high
level demanded by designers and building owners,” said Stan Choiniere, task
force chairman of SPRI’s Retrofit Roof Drain Standard Task
The main differences between retrofit drains and new ones, Choiniere noted,
stem from the need to place them where existing drains already are installed.
This means that capacities must be checked and the connection to existing
plumbing must be leak-free.
Retrofit drains, by their very nature, have smaller drainage diameter than the
original drains because they must fit inside the existing plumbing. Ensuring
sufficient capacity depends upon the retrofit drain diameter, the number of
drain sites and the rainfall expectations for the building location.
Therefore, the retrofit roof standard, ANSI/SPRI RD-1, features a test protocol
designed to assure a leak-free connection to existing piping. Also included are
methods intended to calculate sufficient drainage. An rainfall rate map of the
continental United States
shows maximum one-hour rainfall values with a 100-year return rate. For more
information on this standard, contact SPRI headquarters at info@spri or