In most cities repair and maintenance of hydrants are the responsibilities of the water department. However, in many cases fire department personal perform water supply testing and hydrant inspections. The Silver City Fire Department formed a project to test approx. 800 hydrants in the Silver City area.

Firefighters look for potential problems when checking fire hydrants. Some of which may include the following: obstructions, such as utility poles, or fences too near the hydrant. Common to this area are stone walls. Other potential problems may be: Do the outlets face the proper direction for pumper to hydrant connections, is there sufficient clearance between the ground and the hydrant outlets? Is the hydrant damaged because of traffic accidents? Is the operating stem easily turned? Are there any obstructions (Bottles, cans, rocks) inside the hydrant restricting flow water flow? Does the hydrant drain properly when closed? Any problems found are then referred to the Silver City Water Department for repair or replacement.

Fire Testing and Maintenance

The following kinds of pressure with which the fire department is concerned are : static pressure, normal operating pressure, residual pressure, and flow pressure. Static pressure is measured and is normal pressure existing on a system before a flow hydrant is opened. Normal operating pressure fluctuates during the day and night. It is the pressure found in a system during periods of normal consumption. Residual pressure represents the pressure left in the system at a specific location when water is flowing. The residual pressure at the hydrant is measured and recorded while water is being discharged from another hydrant. The flow pressure is forward velocity pressure at a discharge opening at a hydrant discharge while water is flowing. The velocity of the water stream exerts a pressure that is read on a pitot tube and gauge.

The flow of a hydrant varies for several reasons. First and most obviously, the proximity of feeder mains and the size of the mains to which the hydrant is connected have a major impact on the amount of flow. Sedimentation and deposits within the distribution system may increase the resistance of water flow. Older water systems may experience as decline in flow available.

Hydrant Color Codes

Silver City residents may have noticed that fire hydrants are painted various colors in different areas around town. Firefighters can make better decisions affecting a fire attack if they at least know the relative available water flow of different hydrants in the city. To aid them the Silver City Fire Department has adopted the NFPA system of hydrant class and color coding. Fire hydrants with bonnets painted blue, flow 1,500 gpm or greater and are Class AA. Hydrants painted green are Class A and will flow 1,000 - 1,499 gpm. Class B hydrants are orange and flow 500 - 999 gpm. Red hydrants are considered Class C and flow less than 500 gpm. Another important factor with hydrants painted are the improved visibility when decided to make a hydrant to pumper connection.

Once hydrants are tested, hydrants are then posted on a map showing hydrant location, color codes, and hydrant number. For further information contact Lieutenant Tony Garcia with the Silver City Fire Department at (575) 538-2591 or the Town of Silver City Engineer at (575) 538-3731.