Brennan Q&A September 2003

FIRENUGGETS encourages readers to submit questions to Tom. Your name and department will not be printed unless requested to do so. CLICK HERE to e-mail your questions to Tom.

TOM BRENNAN has more than 35 years of fire service experience having responded to 33,000 fire alarms. His career spans more than 20 years with the Fire Department of New York as well as four years as chief of the Waterbury (Conn.) Fire Department. He has a bachelor of science degree, summa cum laude, John Jay College; Alumnus of the Year Award, John Jay College; chairman of the Connecticut Fire Chiefs Association and a charter member of the National Fire Protection Association, Fire Service Section. He has delivered courses and seminars throughout the United States and has instructed at the National Fire Academy. He was the editor of Fire Engineering Magazine for eight years, is currently a technical editor, and his column “Random Thoughts,” is a regular monthly feature. He is co-editor of The Fire Chief’s Handbook, Fifth Edition. He is the recipient of the 1998 Fire Engineering Lifetime Achievement Award.

SEPTEMBER 2003

Question: Have you heard of a practice of extinguishing a utility electric manhole fire in the street by deliberately filling it with water before the electricity is shut off? I have heard the theory that the water will lower the short-circuit resistance, allowing more electric current to flow in the wires, allowing for any fuses, circuit breakers, or line limiters to open. Thank you.

Answer: Gee, the old classics are rearing their heads. Every 15 years another theory of our involvement in manhole emergencies and fires gets passed around like a firehouse rumor. If you work for me, the answer is simple. Leave the manhole cover alone; protect or move immediate exposures; and prevent humans from arriving in the circle of danger you assign. Now get into the lowest floors and check the utility services that enter the house. Assure that fire has not started in wooden parts of the structure or other combustible storage areas. This is after you call for response of the utility agency with proper urgency commands, depending on conditions. Do not open the cover! Do not open the cover! Gases too rich to burn move into their own explosive range. Do not use water unless directed to by the utility supervisor at the scene. Water can cause all kinds of irreparable damage to equipment below. Trapped water vapor can cause steam explosions and sail the manhole cover anywhere. A flying manhole cover can kill individuals and groups. My father tells of an incident where the cover blew in Manhattan and was never seen again! Leave it alone. Protect the public and uniformed forces. Move exposures, including your apparatus. Call utilities. Examine the service inside the structure surrounding the location, and be prepared to stretch lines and call for assistance if fire extends to the structure. If you don't believe me, make an appointment with the utility service and ask. If the guy tells you to drop water in his manhole, get his name!

* * * * *

Write if you agree or don’t agree or on anything. Tbrennan@firenuggets.com

BACK TO Q & A TABLE OF CONTENTS