Branch Lines

Branch lines connect the steam main to the individual pieces of heat exchange equipment. To maintain proper operation and high efficiency, condensate must be effectively eliminated from branch piping.

Installation Guidelines

Less than 10'(3 m)

More than 10' (3 m)

Valve below

Roll your cursor over the red dots for more information.

The following formulas are expressed as imperial values.
To view this page in SI metric units, click here.

Trap Requirements

Traps are best suited to branch line applications if they:

Have a long service life.
Resist mechanical wear.
Resist corrosion.
Can endure hydraulic shock.
Vent non-condensables at steam temperature.
Perform well on very light loads.
Respond immediately to slugs of condensate.
Handle dirt.
Fail open.
Resist damage from freezing (some cases).

The inverted bucket trap meets all of these requirements best. In non-freezing environments below 30 psig (2 bar), the float and thermostatic trap is an acceptable alternative. An alternate choice in a freezing environment is the thermostatic trap or controlled disc trap.

MATH

To determine trap capacity necessary for installation:

Multiply the Load Calculation Value by the Safety Factor

Safety Factor

The safety factor recommendation for branch lines is 3:1.

Load Calculation

Calculate using a formula

Where:

C =
Condensate in lbs/hr-foot

A =
External area of pipe in square feet
(Table 17-1, Col. 2 below)

U =
Btu/sq ft/degree temperature difference/hr from Chart 17-1 below

t1 =
Steam temperature in °F

t2 =
Air temperature in °F

E =
1 minus efficiency of insulation
(Example: 75 percent efficient insulation:
1-.75 = .25 or E = .25)

H =
Latent heat of steam
(See Steam Table)

* Handbook N-101 (1.3 MB)