How to Remove Condensate
from a Steam Line
Condensate in steam lines causes water hammer, erosion, heat transfer loss, and equipment damage. Proper drainage — using separators, drip legs, and steam traps — is one of the most important and most overlooked aspects of steam system design.
Why Condensate Is Dangerous
Steam condenses continuously as it travels through distribution piping. Even well-insulated lines lose heat. The resulting condensate — liquid water — travels at steam velocity (often 60–100 ft/s) and behaves like a projectile when it hits a fitting, valve, or change in direction.
Water Hammer
Liquid slugs impact pipe fittings with enormous force — cracking valves, flanges, and pipe supports. Often heard as loud banging.
Erosion
High-velocity condensate erodes valve seats, orifice plates, and pipe walls — especially at elbows and reducers.
Heat Transfer Loss
Condensate flooding heat exchangers and coils insulates the heat transfer surface, reducing efficiency by 20–50%.
Equipment Damage
Turbines, control valves, and flow meters are particularly vulnerable to condensate ingestion.
The Three-Layer Solution
Effective condensate management requires three complementary approaches — each addressing a different point in the system:
Mechanical Separation — at the source
A steam separator (centrifugal or baffle type) removes entrained moisture from the steam before it enters critical equipment. Installed upstream of turbines, control valves, and flow meters. Achieves 99%+ moisture removal.
Anderson SeparatorsDrip Legs — along the distribution line
Drip legs are low-point pockets in the steam main that collect condensate by gravity. Properly sized drip legs (minimum 18″ deep, same diameter as the main) prevent condensate from being re-entrained into the steam flow.
Steam Traps — continuous automatic drainage
Steam traps automatically discharge condensate while retaining steam. They are the workhorse of condensate management — installed at every drip leg, heat exchanger outlet, and steam-traced line. Failed-open traps waste steam; failed-closed traps flood equipment.
Clark Reliance Steam TrapsSteam Trap Selection Guide
| Trap Type | Best For | Failure Mode |
|---|---|---|
| Float & Thermostatic (F&T) | Heat exchangers, large condensate loads | Open (steam loss) or closed (flooding) |
| Inverted Bucket | Steam mains, drip legs, high-pressure service | Open on loss of prime |
| Thermodynamic (TD) | Steam tracing, high-pressure, superheated steam | Open (wear) or closed (dirt) |
| Bimetallic | Steam tracing, freeze-resistant applications | Closed (subcooling required) |
Quick Checklist: Condensate-Free Steam System
NCI Products for Steam Condensate Management
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