10 January 2002
ABOVEGROUND HEAT DISTRIBUTION SYSTEMS
7-1. GENERAL. Aboveground distribution systems have the lowest first cost and lowest maintenance
costs of any distribution system described in this manual and are completely designed by the project
designer. This system is a good application for industrial areas and where water tables are high. Many
installations, however, do not desire to have distribution piping above ground for aesthetic reasons.
7-2. SYSTEM DESIGN.
a. Site information. The designer will determine information on the site. The designer will design
all grading for the area and investigate all utilities for conflicts. The designer will provide detailed plans and
profiles of the above ground distribution system routing. Although this system is aboveground, profiles
will indicate system drain and vent points and also potential interferences between the concrete support
piers and any buried utilities.
b. Piping and fittings. All carrier piping and pipe fittings will be carbon steel and will be designed to
satisfy the temperature and pressure requirements of the system. Materials will conform to the
requirements of the guide specification.
c. Pipe supports. The two most common types of aboveground distribution systems are low profile
and high profile.
(1) Low profile system. A typical low profile support is shown in figure 7-1. In this system, the
distribution piping is mounted to concrete piers by means of pipe supports. Typically, the bottoms of the
pipes are mounted no more than 4 feet above grade except at road crossings, which usually incorporate
high profile supports. Typical anchor, free, and guided pipe supports mounted to the concrete piers are
detailed in figure 7-2, figure 7-3, and figure 7-4. Spacing of supports in straight runs of piping will conform
to the support spacing schedule in table 4-2. Provide extra supports, as necessary, at pipe bends and
risers. Requirements for concrete piers and pipe supports are included in the guide specification.
(2) High profile systems. High profile systems are routed high enough to cross roads and avoid
obstructions. Typically the piping will be installed 14 to 16 feet above grade. The system presented in
this manual uses 6-inch concrete-filled pipes embedded in concrete footings as detailed in figure 7-5. The
pipe guides are mounted on channels at the top of the support pipe as detailed in figure 7-6. The pipe
anchors are also mounted to channels and then stabilized with guy cables as shown in figure 7-7.
Structural design for the structural members on these high profile supports in figure 7-6 and 7-7 are for
water filled, schedule 40 steel pipes up to 10-inch nominal size. Conditions out side these constraints
must be designed on a case-by-case basis. The designer for each anchor application will also size the
guy cables. Spacing of supports in straight runs of piping will conform to the support spacing schedule in
table 4-2. Extra supports will be added, as necessary, at pipe bends and risers. Concrete footings and
high profile supports will conform to the requirements of the guide specification.
c. Insulation and jacketing. All piping on aboveground systems shall be insulated and jacketed.
Insulation thicknesses will be determined by insulation tables provided in the guide specification. These
insulation thicknesses were developed using life cycle cost analyses. All insulation will be covered with a
jacketing material in conformance with the guide specification.
e. Expansion Compensation. Expansion loops and bends will be designed as described in chapter 3 of
this manual. Expansion loops will be located to minimize impacts to ground level interferences such as trees
and sidewalks. For horizontal expansion loops, pipe supports will be spaced less than the maximums listed in