5-06M
OUTSIDE STEAM DISTRIBUTION SYSTEMS DESIGN MANUAL
DEPARTMENT OF VETERANS AFFAIRS
1. CRITERIA UNIQUE TO VA:
1.1 Outside steam distribution work includes all steam supply and steam
condensate lines located underground or aboveground outside of buildings.
1.2 Outside steam distribution work shall only be indicated on "MS"-series
drawings (see VA Design and Construction Procedure, "Drawings").
1.2.1 "MS"-series drawings shall include symbols and schedules, details, plot
plans and profiles with interference from other utilities located and
identified, manhole plans and sections, tunnel and trench plans and sections,
location of expansion loops and anchors, demolition plans, other work as
necessary.
1.2.2 Only symbols and abbreviations shown on VA National CAD Standards 15051-
1,2,3 can be used on the drawings.
1.2.3 Pipe sizes shall be indicated on plot plans and on manhole plans and
sections.
1.2.4 Equipment and piping systems shown on the drawings shall be generic and
not the configuration of a particular manufacturer.
1.3 Major options and alternatives must be evaluated utilizing the life cycle
cost analysis methods of NIST Handbook 135 using discount factors from the
current edition of the Annual Supplement to the Handbook.
2. GENERAL:
2.1 Design the outside steam distribution systems to comply with this design
manual, and the current editions of VA Design Guides, VA Design and
Construction Procedures, and the VA Master Specifications. The design shall
also comply with the provisions of the current edition of ASME B31.1 Code for
Pressure Piping, Power Piping. If state or local codes are more stringent
than the above requirements, discuss with the VA Contracting Officer.
2.2 Show outside steam distribution plot plans on drawings using a minimum
scale of 1:250 (1"= 20'). Manhole piping plans and sections shall be drawn
with a minimum scale of 1:30 (3/8" = 1').
2.2.1 Existing work shall be identified in a way which easily distinguishes
this work from the new work. Points of connection between new and existing
work shall be identified.
2.3 The outside steam distribution systems must be designed to provide the
required steam flow and pressure at the point of use. All condensate must be
returned to the boiler plant except where the design of steam-using equipment
prevents this or, for very small loads, when it is not economical.
3. TYPES OF SYSTEMS:
3.1 Pre-Engineered, Factory-Fabricated, Direct Buried Distribution Systems:
These are systems of various manufacturers which include the carrier pipes,
pipe insulation, protective enclosures and accessories. The systems may be
"drainable-dryable-testable" or "water-spread-limiting" as defined in the VA
Master Specification. The "drainable-dryable-testable" system specified is an
enhancement of the standard products of manufacturers. The enhancements
include thicker casings, type and thickness of insulation, superior coating,
thicker end plates, cathodic protection. These enhancements are based on
studies and recommendations made under the auspices of the Federal Agency
Committee on Underground Heat Distribution Systems. The "water-spread-
limiting" system specified is one which, before acceptance on VA projects,
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