Handbook of air conditioning and refrigeration / Shan K

Piping Supports
Piping Insulation
WATER SYSTEMS 7.15
Types of piping support include hangers, which hang the pipe from above; supports, which usually
use brackets to support the pipe from below; anchors to control the movement of the piping; and
guides to guide the axial movement of the piping. Table 7.4 lists the recommended spacing of pipe
hangers. Piping support members should be constructed based on the stress at their point of connection
to the pipe as well as on the characteristics of the structural system. Pipe supports must have
sufficient strength to support the pipe, including the water inside. Except for the anchors, they
should also allow for expansion movement.
Pipes should be supported around the connections to the equipment so that the pipe’s weight and
expansion or contraction do not affect the equipment. For insulated pipes, heavy-gauge sheet-metal
half-sleeves are used between the hangers and the insulation. Corrosion protection should also be
carefully considered.
External pipe insulation should be provided when the inside water temperature 105°F � T w � 60°F
(41°C � T w � 15.6°C) for the sake of energy saving, surface condensation, and high-temperature
safety protection. The optimum thickness of the insulation of pipes depends mainly on the operating
temperature of the inside water, the pipe diameter, and the types of service. There is a compromise between
initial cost and energy cost. ASHRAE/IESNA Standard 90.1-1999 specifies the minimum pipe
insulation thickness for water systems, as listed in Table 7.5. Insulation shall be protected from damage
including that because of sunlight, moisture, equipment maintenance, and wind.
TABLE 7.5 Minimum Pipe Insulation Thickness*, in.
Fluid design
operating temperature
Insulation conductivity
Conductivity, Mean rating
Nominal pipe or tube size, in.
range, °F Btu�in./h�ft2�°F temp. °F