By Bill Adams
In 1930, the Santa Monica (CA) Fire Department purchased a 1,000-gallon-per-minute (gpm) Mack midship pumper with a five-inch rear steamer inlet located just above the tailboard. While not the first custom pumper so equipped, it shows that a rear steamer inlet is not a new innovation. It can be a costly option sometimes cursorily specified by purchasers not realizing how physical characteristics, methods of piping, and ineffectual specification writing can negate perceived benefits.
“Steamer” is a traditional or historical term from the horse-drawn era for the only pump intake on a steam engine-sized for its hard suction hose. Today apparatus manufacturers (OEMs) call them pump suction inlets, suction headers, main pump inlets, or just inlets. I misguidedly call them steamers. Most OEMs call a 2½-inch intake an auxiliary suction-whether or not it is used for drafting.
 |
| 1 This factory delivery photo shows a rear steamer plus two auxiliary 2½-inch rear inlets on a 1966 Mack 1,250-gpm pumper delivered to the Abilene (TX) Fire Department. Fifty years ago, someone thought it easier, faster, and more efficient to have the inlets “where the hose is.” Even the suction sleeve is mounted low. (Photo courtesy of Harvey Eckart.) |
Any pump connection, regardless of size, that can be used for drafting should be called a suction intake or suction inlet. If not designed to draft, call it an auxiliary inlet or an auxiliary intake-again, regardless of size. Knowing the intended use of an inlet will help OEMs in the design and layout process. Purchasers should know the capabilities and limitations of all inlets they are specifying. They owe that to their firefighters and to their taxpayers.
In reviewing one OEM’s specifications for three different 1,500-gpm midship pumpers with rear steamers, all terminated with National Standard Thread (NST) or National Hose (NH) male threads and Storz adapters for five-inch large-diameter hose (LDH). One specified a six-inch rear inlet with four-inch plumbing and a four-inch valve. Another specified a four-inch rear inlet with five-inch piping and a five-inch valve. The last specified a five-inch rear inlet with five-inch piping and a five-inch valve. Why mismatched sizes of piping and valves? Why do they terminate with four-, five-, or six-inch NH threads? The specifications didn’t specify flows required or intended purpose.
NFPA 1901
National Fire Protection Association (NFPA) 1901, Standard for Automotive Fire Apparatus, only uses the terminology intake for connections into a fire pump. Acknowledging nontraditional locations, sentence A16.6.1 in the Appendix says, “Intakes at the front or rear of the apparatus or otherwise specially situated might not allow drafting rated capacity at rated pressure. The purchaser should specify the flow rates required from auxiliary intakes, especially front and rear intakes or other intakes located 10 ft (3 m) or more away from the pump. If auxiliary intakes are provided, the purchaser should also consider requiring the manufacturer to certify the actual flow rates from auxiliary intakes.” Purchasers hardly ever pay attention to that recommendation.
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Posted: May 11, 2016
By Bill Adams
In 1930, the Santa Monica (CA) Fire Department purchased a 1,000-gallon-per-minute (gpm) Mack midship pumper with a five-inch rear steamer inlet located just above the tailboard. While not the first custom pumper so equipped, it shows that a rear steamer inlet is not a new innovation. It can be a costly option sometimes cursorily specified by purchasers not realizing how physical characteristics, methods of piping, and ineffectual specification writing can negate perceived benefits.
“Steamer” is a traditional or historical term from the horse-drawn era for the only pump intake on a steam engine-sized for its hard suction hose. Today apparatus manufacturers (OEMs) call them pump suction inlets, suction headers, main pump inlets, or just inlets. I misguidedly call them steamers. Most OEMs call a 2½-inch intake an auxiliary suction-whether or not it is used for drafting.
|
| 1 This factory delivery photo shows a rear steamer plus two auxiliary 2½-inch rear inlets on a 1966 Mack 1,250-gpm pumper delivered to the Abilene (TX) Fire Department. Fifty years ago, someone thought it easier, faster, and more efficient to have the inlets “where the hose is.” Even the suction sleeve is mounted low. (Photo courtesy of Harvey Eckart.) |
Any pump connection, regardless of size, that can be used for drafting should be called a suction intake or suction inlet. If not designed to draft, call it an auxiliary inlet or an auxiliary intake-again, regardless of size. Knowing the intended use of an inlet will help OEMs in the design and layout process. Purchasers should know the capabilities and limitations of all inlets they are specifying. They owe that to their firefighters and to their taxpayers.
In reviewing one OEM’s specifications for three different 1,500-gpm midship pumpers with rear steamers, all terminated with National Standard Thread (NST) or National Hose (NH) male threads and Storz adapters for five-inch large-diameter hose (LDH). One specified a six-inch rear inlet with four-inch plumbing and a four-inch valve. Another specified a four-inch rear inlet with five-inch piping and a five-inch valve. The last specified a five-inch rear inlet with five-inch piping and a five-inch valve. Why mismatched sizes of piping and valves? Why do they terminate with four-, five-, or six-inch NH threads? The specifications didn’t specify flows required or intended purpose.
NFPA 1901
National Fire Protection Association (NFPA) 1901, Standard for Automotive Fire Apparatus, only uses the terminology intake for connections into a fire pump. Acknowledging nontraditional locations, sentence A16.6.1 in the Appendix says, “Intakes at the front or rear of the apparatus or otherwise specially situated might not allow drafting rated capacity at rated pressure. The purchaser should specify the flow rates required from auxiliary intakes, especially front and rear intakes or other intakes located 10 ft (3 m) or more away from the pump. If auxiliary intakes are provided, the purchaser should also consider requiring the manufacturer to certify the actual flow rates from auxiliary intakes.” Purchasers hardly ever pay attention to that recommendation.
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Posted: May 11, 2016
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Posted: May 11, 2016
Pierce Quamtum cab and chassis; Hale midship 1,500-gpm pump; 560-gallon tank; Cummins ISM engine; Pierce Command Zone™ electronics and control system.
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