Specification Writing

Trench Drain Specification Writing

To write a proper specification for a trench drain or a slotted drain all components of the system must be properly selected.  Before writing the specification calculations for sizing based on flow and loading should be complete.  The specification will clearly define the components of the channel drain and should include all of the following:

  • trench size
  • trench depths at both ends
  • trench body type
  • grate
  • load bearing frame
  • grate locking mechanism
  • outlet pipe size and location
  • joint sealant

Dura Trench uses a specification system where the designer selects each of 7 components and enters each one into a series that allows clear understanding of the project requirements.

SAMPLE SPECIFICATION:

1 2 3 4 5 6 7
TRENCH BODY SLOPE GRATE FRAME LOCK OUTLET SEALANT
DTPF 1% 05B24DI HDBP GLSS 6B SLUR

SLOT 1 – TRENCH BODY

  • DTPF = Prefabricated GFRPC body (polyester resin)​
  • DTCF = Prefabricated GFRPC body (chemical resistant vinyl ester resin)
  • DTFR = Prefabricated fire retardant GFRPC body
  • DTSS = Stainless steel trench body (304 typ, 316 is available)
  • DTTF = Forming system (body is removed for a concrete cast in place trench)
  • DTRPF = True radius precast GFRPC body (polyester resin)
  • DTSP = Prefabricated GFRPC slot drain body
  • DTGP = Galvanized steel slotted pipe
  • DTUTPF = Prefabricated utility trench with standard GFRPC body (polyester resin)
  • DTUTCF = Prefabricated utility trench with chemical resistant GFRPC body (vinyl ester resin)
  • DTUTFR = Prefabricated utility trench with fire retardant GFRPC body
  • DTSH = Stainless steel trench body with flashing collar for membrane applications (304 typ)

SLOT 2 – SLOPE

Typical slopes are 0.5% and 1.0%.  If this slot is left blank, the inverts shown on the plans will be utilized (note that any slope can be specified using this method).  If nothing is shown on the plans a default slope of 0.5% will be utilized.

SLOT 3 – GRATE

Utilize the part numbers of the desired grate in this slot.  Note that when a grate is selected it will by default determine the width of the trench.  Example:  If a 12″ wide grate is selected, a 10″ wide trench drain body will be paired with the grate for a complete system.

SLOT 4 – FRAME

  • LDTP = Light duty thermal plastic frame
  • MDGS = Medium duty galvanized steel frame
  • MDSS = Medium duty stainless steel frame
  • MDAL = Medium duty aluminum frame
  • MDBR = Medium duty brass frame
  • MDBZ = Medium duty bronze frame
  • HDBP = Heavy duty black powder painted frame
  • HDGS = Heavy duty galvanized steel frame
  • HDSS = Heavy duty stainless steel frame
  • HDFG = Heavy duty fiberglass frame
  • EXBP = Extreme duty black powder painted frame
  • EXGS = Extreme duty galvanized steel frame
  • EXDI = Extreme duty ductile iron frame

**Note full part numbers based on sizes can be found in the tables detailing the frames.  Additional options for paver applications and specialty frames are also offered.

SLOT 5 – GRATE LOCKING

  • GLNR = Grate locks not required
  • GLZN = Zinc plated steel grate locks
  • GLSS = Stainless steel grate locks
  • GLVP = Stainless vandal resistant grate locks
  • GL4B = Stainless four corner bolt down of grates
  • GLWCB = Welded and threaded cross bar (material will match frame)

SLOT 6 – OUTLET

List pipe size (1″ through 24″) followed by location (S=side, B=bottom, E=end).  Note that if nothing is specified for pipe outlet the plans will be utilized for outlet selection.

SLOT 7 – JOINT SEALANT

  • NSR = no sealant required
  • SLUR = urethane caulk
  • SLPF = polyester joint sealant
  • SLCF = vinyl ester chemical resistant joint sealant
  • SLWD = weld joints water tight
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