User:IanVG/sandbox/Steam distribution system

A steam distribution system is a part of district utility network with components that carry steam from boilers to consumers for either direct or indirect consumption of steam to satisfy heating, industrial and climate control applications. Steam system can be found in systems providing heating to district level services, such as for cities and university campuses. Steam is also contained in independent systems such as naval air carriers and trains.

The fluid that travels in a steam network is in a two-phase state, with the constantly forming condensate removed via steam traps and drip legs. Because steam is carried more efficiently at higher pressures, proper engineering design and devices are required to prevent phenomena such as water hammer, cavitation, and thermal shockwaves.

Components
A steam distribution system consists of a network of pipelines, boilers, heat exchangers or outlets, steam traps, pumps that ideally comprise a closed loop.

Hazards and mitigation measures
The hazards present in steam distribution system are due to high potential energy in pressurized, heated water.

When condensate is not properly removed and flushed out of the system at a sufficient rate, water in its liquid can accumulate and rapidly accelerate creating a "slug" that can be propelled to speeds as high as .... The resultant collision of the water slug with an elbow or devices can burst pipes and launch equipment at high speeds.This phenomenon is known as water hammer.

Another related hazard is steam hammer, induced by rapid condensation and a subsequent vacuum which due to the massive decrease in volume of the fluid, creates an implosion in the steam coil or pipe. Control valves, isolation valves and system shutdown procedures provide situations for sub-atmospheric pressures. Vacuum breakers can prevent this effect by allowing the intake of air under atmospheric pressure.