|
APPLICATIONS: The Hersey Residential Fire Meter (RFM) is specifically designed for use in residential fire protection systems or combination systems that supply domestic plumbing needs and residential sprinkler fire protection service when installed in accordance with the National Fire Sprinkler Association standards; (Standards for the installation of sprinkler systems in one and two family dwellings, manufactured homes and residential occupancies up to and including four stories in height). The RFM utilizes Hersey's unique vertical turbine measuring element to measure flow rates comparable to traditional positive displacement meters,
yet provides a measuring element that allows suspended particulate matter to pass through the element unobstructed when emergency flow requirements for water are demanded. No other meter provides more flexibility and dependability for measuring water accurately in residential fire suppression and domestic use applications.
CONFORMANCE TO STANDARDS: Each Hersey Residential Fire Service
Meter is tested to assure compliance with ANSI/AWWA Standard C701, Class 1. Each male and female threaded RFM has UL Approval. EnviroBrass II® options conform to the NSF 61 Standard. NFPA 13D or NFPA 13R.
CONSTRUCTION: Hersey Residential Fire Water Meters consist of three basic parts: maincase; rotor assembly; and a permanently sealed register. Maincases and bottom plates are made of bronze for long service life. Rotor assemblies are thermoplastic, which is dimensionally stable and will not corrode. Retro Thrust® rotor design extends the life of the meter by dividing wear between two points: during low flow the tungsten carbide thrust bearing floats against a sapphire bearing surface; during high flow the stainless steel shaft gently contacts a second sapphire bearing. During medium flow, the rotor floats between the thrust bearings without contact. The measuring chamber is protected by an internal strainer with four times the effective straining area of the inlet pipe diameter. No external strainer is required. Fire service connections are easily recognized by the bright red register collar and lid on all visual read meters. Electronic meters are distinguished by the red collar and lense terminal cover on top of the Translator® register.
REGISTER: The permanently sealed register has a unique L seal and heat treated glass to eliminate dirt, moisture infiltration and lens fogging. The totalizing register has a straight-reading odometer type display, a 360˚ test circle with center sweep hand and a low flow (leak) detector.
All Hersey Meter models have electronic meter reading systems available for increased reading efficiency (see Meter Reading Systems).
OPERATION: Water flows through the integral strainer and into the vertical turbine assembly. There, the direction of the water flow is directed by the hub into the rotor at the precise angle necessary for accurate measurement
over the full range of flow rates. No straight pipe requirements apply before or after the meter. The turbine turns freely and rotates in direct proportion to the volume of water passing through the meter. The Hersey turbine operates more quietly than conventional disc or piston meters.
MAINTENANCE: All Hersey Residential Fire Meters are designed and manufactured to provide long service life. The register on all sizes can be replaced without removing the meter from the line. Modular design and economical internal parts allow for inexpensive, speedy rebuilds.
CONNECTIONS: Available with external (N.P.S.M.) straight pipe threads (ANSI B1.20.1) on 3/4" and 1" sizes; internal (NPT) pipe threads (ANSI B1.20.1) on 1-1/2" and 2" sizes.
 |
Model Designation
|
Residential Fire Meter (RFM) |
 |
|
Sizes |
3/4", 1", 1-1/2" and 2" |
|
|
Standards |
Manufactured and tested to meet or exceed all applicable parts of ANSI/AWWA C701, Class 1 Standard All Male and Female Threaded RFMS have UL Fire Service Approval |
|
|
Service |
Cold water measurement with
flow in only one direction |
|
|
Operating
Flow Range |
See Catalog
PDF below |
|
|
Accuracy |
See Catalog
PDF below |
|
|
Maximum Working
Pressure |
175 PSI,
Meets Hydrostatic Pressure Testing to 875 PSI. |
|
|
Temperature
Range |
33ºF TO 100ºF |
|
|
Measuring
Elements |
Rotor |
|
|
Strainer |
4 times the inlet pipe diameter
of straining surface area with .080 perforations. |
|
|
|
Register
Type |
Straight reading, permanently sealed, magnetic drive with low
flow indicator. Remote reading units optional |
|
|
Meter Connections |
1/2", 3/4" and 1" external (NPSM) straight pipe threads, 1-1/2 size and 2" size
available with internal thread (NPT) ends same nominal size as size of meter.
|
|
|
Materials |
Maincase -
bronze UNSC84400; Rotor assembly - thermoplastic; Strainer
- stainless steel; Casing bolts - stainless steel ANSI B18.
|
|
|
Options |
Meter case - EnviroBrassII® UNSC89520, Spuds and Spools with test ports on 1-1/2" and
2" meters to accommodate standard AWWA laying lengths,
Translator registers and AMR Systems
|
|
