10 January 2002
1-1. PURPOSE AND SCOPE. This document provides criteria and guidance for the design and
construction of heating and cooling distribution systems and supplements information in the "Notes to
the Designer" of the guide specifications. These distribution systems include Heat Distribution
Systems in Concrete Trenches, Pre-engineered Underground Heat Distribution Systems, Prefabricated
Underground Heating/Cooling Distribution Systems, and Aboveground Heat Distribution Systems. The
mediums used in these distribution systems, as defined by the Department of Defense (DoD), include:
a. High temperature hot water (HTHW) (251 deg. F to 450 deg. F)
b. Low temperature hot water (LTHW) (150 deg. F to 250 deg. F)
c. Low pressure steam systems (up to 15 psig)
d. High pressure steam systems (over 15 psig)
e. Condensate return systems (up to 200 deg. F)
f. Chilled water systems.
1-2. APPLICABILITY. These instructions are applicable to all \ DoD agencies /2/ and their
contractors involved in the design and construction of heating and cooling distribution systems.
1-3. REFERENCES. Appendix A contains a list of references used in these instructions.
1-4. EXCEPTIONS. Generally, this document covers heating and cooling distribution systems most
typically installed on United States military installations. However, deviations from the recommendations
of this manual may be necessary when unusual site conditions are present or specific using service
requirements are encountered. For example, the manual does not discuss design problems associated
with arctic and subarctic construction, in which case, the designer should refer to the "Cold Climate
Utilities Manual", 1986, Canadian Society of Civil Engineers, Montreal, Quebec.
1-5. DEFINITIONS. The term "designer" used throughout this manual refers to the person or persons
responsible for preparing contract drawings and specifications for a heating or cooling distribution
design. The main engineering discipline areas of the "designer" are:
a. Mechanical. Includes expansion compensation, stress analysis, piping system design (fittings,
valves, insulation), equipment selection and sizing, and pipe sizing and routing.
b. Structural. Includes reinforced concrete design, pipe supports, and valve manhole cover
c. Electrical. Includes cathodic protection, electrical service and controls (e.g. sump pumps).
d. Civil. Includes earth work, road crossings (for buried systems), system plans and profiles, and