HomeMy WebLinkAboutC_Corresponsence_Fitz James_PGIS_180214_v1AIRSAFE
PO Box 287
Greenbank, WA 98253
(360) 678-0345 (office)
(360) 320-2131 (cell)
November 17, 2017
Mr. Ian Fitz-James, P.E.
City of Renton
Via e-mail
RE: Southport Office Helipad/2017 Renton Surface Water Design Manual/Stormwater Comments
Dear Ian:
After reviewing your comment about this proposed helipad as it relates to treatment of storm water runoff
and reading relevant sections of the surface water manual I am asking for reconsideration of the
classification of this proposed facility as a pollution generating impervious surface (PGIS) prior to our
submittal for a conditional use permit.
The manual states that PGIS are those areas that are “subject to vehicular use.” The term vehicular use in
a separate section incorporates aircraft. The process used therefore to initially determine this proposed
landing area a PGIS is logical.
The term aircraft covers a wide range of vehicles that fly. Many fixed-wing aircraft and older,
reciprocating engine helicopters do leak fluids. Such leakage is what the manual wishes to address. I
suggest that the Southport Office Helipad even though it is designed to accommodate aircraft should not
be considered a pollution generating surface because modern, light-turbine helicopters are immediately
taken out of service if they leak fluids of any kind.
Prior to the 1990 version of NFPA 418 “Heliports,” there existed a requirement for oil/water separators at
elevated helicopter landing areas. From the early 1970s when helicopters began landing on rooftops,
mostly in support of emergency medical service operations, Korean War vintage helicopters were used.
They did leak and codes were developed to require capture and treatment of that leakage.
During a meeting of the NFPA heliport committee as the 1990 version of 418 was being amended the
oil/water separator requirement was removed as the committee recognized one of the differences between
reciprocating engine helicopters and turbine helicopters to be an absence of leakage. This was confirmed
during a phone and e-mail exchange with Paul May NFPA staff liaison fire protection engineer in March,
2008.
As I am sure you are aware, codes, regulations, and manuals should be reviewed and applied according to
their literal meaning and, where appropriate, their intent. While this proposed helipad is planned to
accommodate aircraft I suggest classifying it as a PGIS is not consistent with the intent of the manual due
to the absence of leakage and therefore an absence of need to treat.
David C. Ketchum
Airsafe
CC: Ms. Rocale Timmons, Seco Development, Inc.