This article was written by Brian Bannon & Meghan Dubielewicz
Around the world, hundreds of thousands of steam valves are leaking or malfunctioning. Mechanical contractors are fixing, replacing or just simply attempting to help their client maintain the valve to keep it going. Valve failures vary. Some of these failed valves have a buildup of tuberculation or debris, or the operating nut will not turn in either direction. Perhaps your gate valve is leaking between the body and the bonnet, which is usually a pretty quick fix by tightening the bonnet bolts and nuts. What is the one thing that all these valves have in common?
This is a common sight when you walk through a facility that uses steam. Truly understanding how much energy that uninsulated steam valve is losing each year is not so common. Each uninsulated gate valve, wye strainer and pressure reducing valve is losing hundreds of dollars per year. The table below shows how many BTU’s per hour a standard gate valve loses.
Operating Temp F° |
Size of Gate Valve in Inches |
||||
3 | 4 | 6 | 8 | 10 | |
200 | 800 | 1,090 | 1,560 | 2,200 | 2,900 |
300 | 1,710 | 2,300 | 3,300 | 4,800 | 6,200 |
400 | 2,900 | 3,400 | 5,800 | 8,300 | 25,200 |
source: https://www.nrel.gov/docs/fy12osti/52762.pdf
One 6" gate valve is losing $508.00 per year!
Annual Fuel Savings =
5,800 Btu/hr Χ 8,760 hr/yr ÷ (0.80 efficiency) = 63.51 MMBtu
*Interpolating from the table above, calculate the annual fuel and dollar savings from installing a 1-inch thick insulating pad on an uninsulated 6-inch gate valve in a 250-pound-per-square-inch-gauge (psig) saturated steam line (406°F). Assume continuous operation with natural gas at a boiler efficiency of 80% and a fuel price of $8.00 per million Btu ($8.00/MMBtu).
This is where the lonely valve’s life starts. The mechanical contractor doesn't perform pipe insulation and usually subcontracts this work out. The client does not want to pay for an insulator to come out and insulate one valve. Everyone convinces himself or herself that they will call an insulator when there is more work to do. Years go by and the valve remains uninsulated.
As the insulation industry adopts new technology, the lonely uninsulated valves will not remain uninsulated for very long. Thermaxx is making sure of this!