Steam Water Hammer & CHW Articles
by Wayne Kirsner

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If you're trying to understand water
hammer in steam systems, Link to
my reading recommendations below.

To date, These articles have been cited in 69 other journals and research papers

Chemical Engineering Magazine, August 2012.

"There’s a temptation that steam design engineers find difficult to resist— putting condensate from high pressure steam mains directly into the low pressure pumped condensate return mains. After all, the condensate return (CR) main is so-o convenient--it’s generally laid right next to the outgoing steam main in the same tunnel, trench or racks as the CR main returning to the

steam plant. And the good practice alternatives to dumping the condensate directly into the pumped CR, e.g., running a dedicated separate high pressure condensate return pipe back to the Plant, or, if a user’s flash tank is not near, flashing the condensate in a small vented tank at each trap then pumping it back into the CR main seem like swatting a fly with a sledge hammer". This article explains what works (and what doesn't) to avoid waterhammer in condensate return lines. Download article in PDF format (264k).

BP Process Safety Booklet: Hazards of Steam

For British Petroleum, rewrote Chapter 10 and 11 for revision of their safety booklet . Chapter 10, "Water in Steam Lines", is a basic but comprehensive tutorial on how and why waterhammer can develop in a steam system. Chapter 11 entitled "Example of a Waterhammer in a Steam System" explains the June 7, 2000 explosion of an 18 in. steam pipe at the BP Plant in Grangemouth, Scotland. This material is the property of British Petroleum and the author and should not be reproduced from this web site without their permission. View my unpublished version .

Bangin' in the Boiler Plant !
Sept. 2003 HPAC Engineering Magazine
Each time [the feedwater] pump goes On or Off, it makes a terrible bang, and pipes shakes like creazy. Anyone have a idea how to eliminate (or decrease) water hammering in the steam boiler feeding line? --Posted on May 22, 2002 at
If there is water hammer when a condensate or feedwater pump starts, especially if the fluid being pumped is at or near its saturation temperature, the cause of the hammering is probably Column-Closure Waterhammer . The term "column-closure waterhammer" is little known to HVAC

engineers and power plant operators because, unlike Condensation-Induced Water hammer, it generally does not lead to catastrophic steam ruptures and operator deaths and, thus, has remained largely anony-mous in the non-nuclear engineering world. Like its potentially more potent cousin, however, Column-Closure Waterhammer is a common type of water hammer in steam systems. In this article, I explain the mechanism of Column-Closure Waterhammer, then examine, one by one, the most common types of water hammer events I find in boiler plants. To fully grasp this article, one should understand Condensate-Induced Waterhammer. (See the article below Understanding Condensation Induced Water Hammer).Download Author's Un-edited Version in PDF format .

Flooded Manholes & Submerged Steam Lines Understanding the Danger of Nucleate Boiling!
Flooding of a manhole or culvert containing a live steam line is more dangerous than people imagine. In a nutshell, if flooding submerges a high pressure steam main causing insulation to slough off the line or other-wise become ineffective, the heat transfer regime from the surface of the pipe to the surrounding flood water will likely transition to "nucleate boiling". The rate of heat transfer due to nucleate boiling is on the order of 1000 times greater than that normally expected from an insulated steam main. Essentially a steam main submerged in flood water becomes a condenser generating hundreds of pounds of condensate per linear foot of pipe. Steam traps, even though they typically have a safety factor on the order of 25 times that needed to drain a well- insulated system, cannot handle this condensate load. (1st Qtr 2002 issue of District Energy Magazine and May 2002 HPAC Engineering Magazine. Click pdf for May 02 HPAC Magazine Article, Download article in PDF format (16k)
Heating/Piping/Air Conditioning, July 1999, Wayne Kirsner, PE

At Brookhaven National Laboratory in 1986, four men working in a utility vault were engulfed by steam when waterhammer blew out the gaskets in the steam main. Two men died; two survived. Why? Download article in PDF format (176k) pdf compliments of HPAC

Condensation Induced

Published in Heating/Piping/Air Conditioning Magazine, Jan 1999, by Wayne Kirsner, PE. Republished by the Canadian Institute of Power Engineers, April, July 2005.

This article describes a steam explosion that took place at Ft. Wainwright Alaska as asbestos workers were removing insulation from a live steam main. It explains the mechanism of condensation-induced waterhammer in the context of that accident. If you're going to get a grip on understanding water hammer in steam systems, you need to understand condensation-induced waterhammer. The pdf below is furnished compliments of HPAC.

Condensation Induced Waterhammer (PDF Version 571k)

Condensation Induced Waterhammer (Text version 216k)

Published in Heating/Piping/Air Conditioning, July 1995 and in National Engineer, the Journal of the National Association of Power Engineers, Feb 1996

Based on a fatal accident at Northwest Georgia Regional Hosital in Rome, GA where a steam operator was killed while admitting 110 psi steam to a section of cold steam main. The artical describes the investigation into the factors contributing to a little understood class of steam system accidents--"condensation induced water hammer"-- and how accidents like this can be avoided . Download article in PDF format (520k) pdf furnished compliments of HPAC
text version scanned version

Is Reducing Boiler Steam Pressure Such a Hot Idea?

HPAC Magazine, December 1987.

Exposes the oft-times erroneous energy saving justification for reducing boiler steam pressure, discusses the actual potential energy savings, then enumerates the pitfalls of lowering systemsteam pressure that the engineer will need to avoid. This was Mr. Kirsner's first article published in a major engineering magazine.

Click to go to artice followed by follow-up debate in April 1988 issue of HPAC Magazine

When Removing Insulation Turns Deadly--Insulation Outlook Magazine, June 2000

Removing insulation from live steam lines accelerates condensate formation and subcooling--two prerequisites for explosive Condensation Induced Water hammer. This article explains that removing insulation from a long length of live steam line is a risky proposition. Link to my original unedited submission for the article.

Chilled Water Articles by Wayne Kirsner

"Designing for 42 degree F Chilled Water--Does It Save Energy?"

ASHRAE Journal, January 1998, Wayne Kirsner, PE

This article is a sequel to "3 GPM/ton Condenser Water Flow--Does it Waste Energy" first published in the February 1996 Journal.

Download the article in PDF format (900k)

pdf furnished compliments of ASHRAE

A Check Valve in the Chiller Bypass Line? Two Views on This Question

Heating/Piping/Air Conditioning , Jan 1998 , Wayne Kirsner, PE; J. Rishel, PE

A two-part article appearing side-by-side in the same issue. Part 1 is by Kirsner; he discusses rectifying the primary-secondary loops in CHW plants to deal with low delta-T syndrome. Part 2 is by Rishel; he discusses system analysis vs. quick fixes for existing chilled water systems.

Download article in PDF format (133k)

pdf furnished compliments of HPAC

The Demise of the Primary-Secondary Pumping Paradigm for Chilled Water Plant Design

Heating/Piping/Air Conditioning, Nov 1996, Wayne Kirsner, PE

Recognizing the need to seek design solutions that can cope with or prevent low delta-T chilled water plant syndrome.

Download article in PDF format (69k)

pdf furnished compliments of HPAC

Troubleshooting Chilled Water Distribution Problems at the NASA Johnson Space Center

Heating/Piping/Air Conditioning, Feb 1995, Wayne Kirsner, PE

Discovering the cause of chilled water distribution problems at the NASA Johnson Space Center could help improve system efficiency.

Download article in PDF format (385k)

pdf furnished compliments of HPAC

Other Feature Articles: Publications

"3 GPM/ton Condenser Water Flow -- Does it Waste Energy?"--February 1996 issue of the ASHRAE Journal.

3 GPM/ton Condenser Water Flow (PDF Version 463k)


Recommended Reading to Understand
Waterhammer in Steam Systems

Start out with the Waterhammer Quiz on the home page. It will give you a reality check on what you don't know. Then read the article "Condensation Induced Waterhammer" first. It's supposed to be comprehensive. The BP Safety Booklet chapters are also comprehensive, but may be too succinct. After studying the article, view the two waterhammer videos on my home page several times.

The "Banging in the Boiler Plant" article is primarily about column-closure waterhammer--not as important as condensation-induced waterhammer. The "Flooded Manholes and Submerged Steam Lines" article is important if your site is ever subject to flooding. The "Surviving a Steam Rupture..." article is informative and short, but not important. "What Caused the Accident that Killed Jack Smith" may be good but I haven't reread it in a long time and I've learned a lot since I wrote it in 1993.

If you having waterhammer in, or are designing a condensate return system in which high pressure/high temperature condensate will be dumped upon subcooled condensate, it's imperative to read and understand the article ' Waterhammer in Condensate Return Systems".

There are some other interesting historical articles on waterhammer in steam systems written in the 19th, early 20th and mid 20th century available at the bottom of my home page. They're amazingly prescient.

I hope this is good advice. Write me if you can improve on it.