Page 275 - Facility Piping Systems Handbook for Industrial, Commercial, and Healthcare Facilities

HEAT TRANSFER, INSULATION, AND FREEZE PROTECTION

HEAT TRANSFER, INSULATION, AND FREEZE PROTECTION 5.59

2. From the steam supply location, determine whether a pressure-reducing sta tion is
required. Locate the manifold for a multiple tracer system. Based on the pressure avail-
able, select a subheader size from Table 5.21 [30 to 50 psig (210 to 350 Kpa) steam] or
Table 5.22 [100 to 150 psig (700 to 1050 kPa) steam]. With the proposed tracer line size
and the steam pressure available, select the subheader size to supply the selected number
of tracer lines based on the steam pressure. Accepted practice limits subheader size to
approximately 50 ft (15 m).
3. To find the longest allowable heat tracing pipe run, use Table 5.23, entering the table
with the available steam pressure and the line size. Another factor in the design of the

TABLE 5.21 Subheader Size Using 30 to 50 psig (210–350 kPa) Steam Pressure

Maximum number of Maximum number of
3
tracers 8 -in (12-mm) O.D. tracers 2 -in (15-mm) O.D. Subheader pipe size, in DN
1
1–4 1–2 3 4 20
5–9 3–5 1 25
1
10–22 6–16 1 2 40

TABLE 5.22 Subheader Size Using 100 to 150 psig (700–1000 kPa) Steam Pressure

Maximum number of Maximum number of
3
1
tracers 8 -in (12-mm) O.D. tracers 2 -in (15-mm) O.D. Subheader pipe size, in DN
1–5 1–3 3 4 20
7–12 4–7 125
1
13–30 8–24 1 2 40

TABLE 5.23 Heat Tracer Length
1
Tracing design: 2 -in O.D. tubing—parallel to pipe maximum tracing run per trap (ft) 1
Steam pressure, kPa

10 50 100 150 200 250
Line size, in DN 70 350 700 1,050 1,400 1,750
Single tracer
1 25 230 270 290 360 430 450
1 2 40 190 230 250 310 360 390
1
2 50 170 210 220 270 320 350
3 80 140 170 180 240 260 280
4 100 130 150 160 210 220 230
6 150 100 120 130 160 170 200
Double tracer
8 200 50 60 70 80 90 100
10 * 250 100 120 130 160 170 200
12 * 300 100 120 130 160 170 200
14 * 350 50 60 70 80 90 100
1
ft = 0.305 meters
* 3
Use 4 -in O.D. tubing for tracer.

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