Looking for more information about a Reliable product?

Our Technical Services team has compiled a list of frequently asked questions to help you get the information you need. Jump to a specific topic using the links below.

Can't find what you're looking for?

Contact Technical Services at technicalservices@reliablesprinkler.com or call Connie Seaborn at 1.800.55.RASCO (72726) or 864.843.5227.


Sprinklers

  1. What is the liquid in your glass bulb sprinklers?
  2. Why are the bulbs different colors?
  3. Why are the bulbs different sizes?
  4. How can I distinguish between a Reliable Sprinkler and another manufacturer's?
  5. I need a corrosion resistant/proof sprinkler, what do you recommend?
  6. What are the pressures and flows for the Model G Recessed Automatic Sprinkler?
  7. Are there any height restrictions on the Reliable Model G VELO Pendent and the GXLO Upright Sprinkler?
  8. Why do you not show the minimum spacing on all sprinklers in your bulletins?
  9. What are the pressures and flows for your standard spray sprinklers?
  10. Can I use a different ceiling plate with your sprinklers?
  11. Can your (SWC) concealed horizontal sidewall sprinkler be used in NFPA 13R systems?
  12. Does Reliable make a "Large Drop Sprinkler"?
  13. Does Reliable make a "Stainless Steel" sprinkler?
  14. How should dry sprinklers be installed?
  15. Why does Reliable make both solder link and bulb sprinklers?
  16. Why does Reliable not install sprinklers as well as manufacture them?
  17. How do I determine the proper temperature rating for my sprinklers?
  18. Is the retaining flange required for installation of Reliable Institutional Sprinklers?
  19. Does Reliable make a non-ferrous sprinkler for MRI Rooms?
  20. What is a sprinkler identification number and what does it mean?
  21. Is the installation of the retaining flange provided with the Model XL institutional sprinkler escutcheon kit a UL Listing requirement?
  22. Is there a listed/approved sprinkler guard for institutional sprinklers?
  23. Are there listed/approved sprinkler guards for commercial extended coverage or residential sprinklers?
  24. Are there listed/approved corrosion-resistant coatings for quick response or sprinklers containing fast-response thermal elements?
  25. How do I determine which sprinkler temperature rating to when designing a sprinkler system?
  26. Does Reliable make sprinklers that can be used with foam systems using foam liquid concentrates?

What is the liquid in your glass bulb sprinklers?

The liquid used in our glass bulb sprinklers is a non-toxic proprietary glycerin solution that that expands when heated.

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Why are the bulbs different colors?

The different colors designate various temperature classification ratings in accordance with NFPA 13.

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Why are the bulbs different sizes?

The different size bulbs determine the type of sprinkler response. 5mm bulbs are used for standard response sprinklers; 3mm bulbs are used for quick response sprinklers; 2.5mm bulbs are used for ESFR's.

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How can I distinguish between a Reliable Sprinkler and another manufacturer's?

The RASCO marking is indicative of a Reliable manufactured product. Additional information can be found on the sprinkler deflector.

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I need a corrosion resistant/proof sprinkler, what do you recommend?

Reliable offers several UL Listed corrosion-proof coatings. These coatings are available in 165°F clear wax, 212°F brown wax (for intermediate temperature rated sprinklers), lead plated, and wax over lead. Generally, these are used with standard response sprinklers only.

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What are the pressures and flows for the Model G Recessed Automatic Sprinkler?

The Model G Recessed Automatic Sprinkler is a standard spray pendent sprinkler available with different orifices and K Factors. The amount of water required is dependant on the spacing and density requirements in accordance with NFPA 13. You must calculate the pressure required using the formula Q = K√(P) calculate the flow or  P = (Q/K)² to  determine the pressure.  NFPA 13 requires a minimum pressure of 7 psi.

Q = Flow (in gpm)

K = K Factor

P = Pressure (in psi)

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Are there any height restrictions on the Reliable Model G VELO Pendent and the GXLO Upright Sprinkler?

NFPA 13 has no height restrictions. Since these sprinklers are NFPA 13 sprinklers. There is no height restriction.

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Why do you not show the minimum spacing on all sprinklers in your bulletins?

Reliable indicates the minimum spacing on all sprinklers that differ from NFPA 13, NFPA 13R and NFPA 13D. If not shown in the bulletin, the minimum spacing is as allowed by NFPA.

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What are the pressures and flows for your standard spray sprinklers?

Standard spray sprinklers both quick response and standard response are control sprinklers, and the minimum pressure is 7 psi as per NFPA 13. Any pressure above that is calculated based on density (GPM per Sq. ft.) required for your design. The amount of flow in GPM is based on the density curves in NFPA 13. The pressure to achieve that flow is based on the sprinkler spacing and the K Factor of the sprinkler and the pressure available based on your design and the available water supply. You must calculate the flow required using the formula Q= K√(P) and P = (Q/K)² to determine the pressure.

Q = Flow (in gpm)

K = K Factor

P = Pressure (in psi)

With Extended Coverage, Residential and ESFR the pressures and flows are listed for each of the sprinklers based on the distribution and fire tests conducted on each at the laboratories.

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Can I use a different ceiling plate with your sprinklers?

Recessed and concealed sprinkler ceiling plates are listed with the sprinkler and any ceiling plate used with recessed or concealed must be listed for the sprinkler. Other than those, you can use any ceiling plate that does not exceed the deflector distances in NFPA 13.

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Can your (SWC) concealed horizontal sidewall sprinkler be used in NFPA 13R systems?

The Reliable SWC concealed horizontal sidewall can be used in Light Hazard applications as defined in NFPA 13 and NFPA 13R. They cannot be used in residential applications as defined in NFPA 13D. You should always check for state or local requirements that might differ from the NFPA codes.

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Does Reliable make a "Large Drop Sprinkler"?

No, currently Reliable does not manufacture a large drop sprinkler. Our research and development efforts have been directed toward the ESFR technology but the large drop is on our development list.

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Does Reliable make a "Stainless Steel" sprinkler?

No, currently Reliable does not manufacture a stainless steel sprinkler. Our research and development efforts have been directed toward the other special application sprinkler technology but a stainless steel is on our development list.

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How should dry sprinklers be installed?

Dry sprinklers should always be installed in the side outlet of a tee. The dry sprinkler is designed to extend up into the fitting to prevent the accumulation of deposits on top of the sprinkler. Dry sprinkler should never be installed in an elbow or coupling. Installation in an elbow or coupling can impede the operation or allow deposits to accumulate on the top of the dry sprinkler. Additionally, in freezers Reliable recommends that dry sprinklers extend at least 14 inches above (outside) the freezer wall or ceiling. It is often a good idea to insulate the dry sprinkler and seal the hole made in the freezer inside and outside the freezer wall or ceiling. If the freezer contains food products, make sure the sealant you use is FDA Approved. Dry sprinklers are required to be inspected and tested every 10 years in the latest edition of NFPA 25.

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Why does Reliable make both solder link and bulb sprinklers?

Reliable has been a leader for years in solder link technology where solder link technology is appropriate. Reliable uses bulbs where the need for aesthetics or other design considerations dictate their use.

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Why does Reliable not install sprinklers as well as manufacture them?

Reliable chose many years ago not to compete with our customers and we do not compete with our customers today. Reliable's mission is to provide our customers the latest in quality fire sprinklers products manufactured by Reliable utilizing the latest in new technology as well as distribute other quality fire protection products manufactured by selected vendors.

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How do I determine the proper temperature rating for my sprinklers?

The maximum ambient ceiling temperature that the sprinkler will be exposed to on a daily basis determines the appropriate sprinkler temperature rating, except where the NFPA standards may dictate the temperature rating for design considerations. Even then, one must still consider the maximum ambient ceiling temperature anticipated on a daily basis. Ambient temperatures in excess of these maximums would cause stress on the thermal element, eventually weakening its load carrying capacity and possibly causing the sprinkler to operate prematurely. Refer to the Temperature Ratings, Classifications, and Color Codings Table in NFPA 13.

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Is the retaining flange required for installation of Reliable Institutional Sprinklers?

The retaining flange is not a required item regarding the listing of the sprinklers. It provides an option to the contractor as a method of securing the piping to prevent axial or lateral movement of the sprinkler either away from the ceiling or the wall by an occupant. If it is not used because of installation constraints, some other approved method of securing the pipe must be provided to prevent an occupant from inflicting self-injury.

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Does Reliable make a non-ferrous sprinkler for MRI Rooms?

Yes. An excellent choice for MRI rooms is the Reliable Model Model F4FR-NF, a non-ferrous concealed sprinkler specifically tested for use in MRI rooms. This is the only concealed sprinkler actually tested in a laboratory with a magnetic field of 6 Tesla. The highest clinical magent system commercially available today produces a magnetic field of 3 Tesla.

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What is a sprinkler identification number and what does it mean?

Beginning in January of 2001, all manufacturers were required to assign a five digit alpha-numeric code called the sprinkler identification number (SIN) for each sprinkler. This was to comply with the marking requirements stated in paragraph 3-2.2 of NFPA 13, 1999 edition. The SIN number can be compared to Reliable technical bulletins to verify the model, deflector style, K-factor and thermal sensitivity of the sprinklers. Reliable SIN numbers begin with either "R" or "RA" and are followed by four numbers. The first two numbers identify the last two numbers of the Reliable technical bulletin associated with that sprinkler; the last two numbers identify the deflector style and the K-factor range, respectively. All SIN numbers are located on the sprinkler deflector. "Pintle" screws (small metal protrusion extending above or beyond the sprinkler deflector), which were used to identify sprinklers using other than standard orifice/thread combinations, will be phased out.

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Is the installation of the retaining flange provided with the Model XL institutional sprinkler escutcheon kit a UL Listing requirement?

No, installation of the retaining flange is not a UL Listing requirement. The tamper resistant and self-injury prevention features of institutional sprinklers are not part of the UL Listing. They are design features provided by the sprinkler manufacturer. For maximum tamper resistance, it is the responsibility of the installing contractor to secure the nipple on which the sprinkler is installed to prevent the sprinkler and escutcheon assembly from being pulled away from the wall or ceiling. The retaining flange is provided as a way of securing the branch line piping, in the form of a nipple or arm-over, to prevent pipe movement initiated by the room occupant. If the retaining flange cannot be used due to larger piping or over-sized wall sleeves, alternative devices approved by the installing contractor or design engineer may be used to secure the piping from movement.

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Is there a listed/approved sprinkler guard for institutional sprinklers?

No, there are no listed/approved sprinkler guards for institutional sprinklers. Incorporating security and self-injury prevention features for such a sprinkler guard would impede and hinder sprinkler performance.

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Are there listed/approved sprinkler guards for commercial extended coverage or residential sprinklers?

No, there are no listed/approved sprinkler guards for extended coverage or residential sprinklers. Because of the extended discharge requirements and low flow characteristics associated with these types of sprinklers, the sprinkler guard would act as a significant obstruction to sprinkler performance, requiring greater flows and pressure to meet listing/approval requirements.

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Are there listed/approved corrosion-resistant coatings for quick response or sprinklers containing fast-response thermal elements?

No, only standard response sprinklers can be listed/approved with corrosion resistant coatings. Such coatings would adversely affect the sensitivity of a quick response or fast response thermal element, causing the sprinkler to meet only standard response sensitivity criteria.     

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How do I determine which sprinkler temperature rating to when designing a sprinkler system?

Sprinkler temperature rating is based on the following:

  • Maximum expected ambient temperature a sprinkler will be exposed to on a daily (or seasonal) basis
  • Proximity of sprinklers relative to heat sources
  • Design densities chosen for storage applications based on storage area/density curves

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Does Reliable make sprinklers that can be used with foam systems using foam liquid concentrates?

Yes. However, sprinklers are listed/approved with a specific manufacturers foam concentrate. Once must reference the UL Fire Protection Equipment Directory section on Foam Liquid Concentrates (GFGV) or the Foam manufacturer's cut sheets to determine which Reliable style sprinkler is listed/approved for use with the specific foam concentrate.

Does the Specific Application Listing stated for the Reliable Model G XLO and G VELO storage sprinklers limit their use only to the criteria specified in the application listing, or can they be also be used as area/density sprinklers used in accordance with NFPA 13, NFPA 231 and NFPA 231C?

The Reliable Model G XLO and G VELO sprinklers are cULus Listed and FM Approved as control-mode, area/density spray sprinklers for NFPA 13, 231, 231C storage applications. These sprinklers can be used in one of two ways. First, they can be used as area/density sprinklers in accordance with the storage design requirements of NFPA 231, 231C and NFPA 13, or FM Global Data Sheets. This design criteria is based on the use of the appropriate area/density curves in the respective standard as a function of the type of commodity, storage height and configuration, sprinkler temperature rating, etc.

Second, these sprinklers can be used as specific application sprinklers, based on the cULus Specific Application Listing criteria stated in the Reliable literature. This specific application listing is an ADDITIONAL LISTING that must meet the specific application criteria.

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Valves

  1. Why is the Model G Riser Check Valve for the LDX Dry Pipe Valve System gray?
  2. What is the difference between the Model E3 variable pressure trim and constant pressure trim?
  3. Does the DDX deluge valve require a check valve for preaction system applications?
  4. What is the capacity needed for the open drain of my sprinkler riser?

Why is the Model G Riser Check Valve for the LDX Dry Pipe Valve System gray?

Because of approvals and clapper construction, the gray color code is used to differentiate the Model G Riser Check Valve used for the LDX System from the black color of the Model G Riser Check Valve used for preaction systems.

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What is the difference between the Model E3 variable pressure trim and constant pressure trim?

The only difference between these two trims is the addition of a Model E1 retard chamber.

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Does the DDX deluge valve require a check valve for preaction system applications?

No, the DDX utilizes an intermediate chamber in its seat design, which separates the inside of the valve body with the alarm outlet piping which is open to atmosphere. Therefore, supervisory air pressure can fill the valve body and the system piping without separation by a riser check valve.

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What is the capacity needed for the open drain of my sprinkler riser?

All sprinkler systems should be properly drained. The drain outlet or drain manifold outlet should be piped to an open drain able to handle this capacity, as well as assist in providing proper drainage for a main drain test. To estimate the total flow from the drain connection of various drain sizes, the following formula can be used:

Q = K√P  where

Q = drain flow in gallons

K = Drain angle valve K-factor (K-factor based upon angle valve manufacturer's data)

P = Water Supply Pressure

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Valve Accessories

  1. How do I adjust the pressure switch on the Model B-1 Pressure Maintenance Device?
  2. What is the difference between an accelerator used with a Model D dry valve and an accelerator used with the DDX-LP Low Pressure Dry System?
  3. Are air compressors required to be UL Listed or FM Approved?

How do I adjust the pressure switch on the Model B-1 Pressure Maintenance Device?

The pressure switch used on the Model B-1 pressure maintenance device is a Furnas Model 69H. Removing the cover, one finds two adjustment screws: a large metallic screw for adjusting the cut-in pressure (the pressure at which the compressor comes on as system pressure decreases); and a small metallic screw for adjusting the cut-out pressure (the pressure at which the compressor shuts off on rising pressure. Turn the large screw clockwise to increase both cut-in and cut-out pressure, and turn the small screw clockwise to increase the cut-out pressure without affecting the cut-in pressure.

Procedure

Wire the compressor and B-1 pressure maintenance device pressure switch in accordance with the wiring diagram. Start with no pressure and energize the circuit. The compressor should start immediately. Allow the compressor to run until it shuts down, recording the pressure reading. This is the current cut-out pressure setting. Next, bleed the air pressure out of the system, watching the air pressure gauge, until the compressor restarts and note the pressure reading. This is the current cut-in pressure setting. If the cut-in point needs to be changed, adjust the large metal screw after the compressor stops. Repeat the bleeding and adjusting until the cut-in pressure is correct. Each time the compressor stops, note the cut-out pressure which will be changing each time you adjust the large metal screw.

After the cut-in pressure is set to the desired setting, adjust the small metal screw to raise or lower the cut-out pressure from the last noted pressure reading and repeat the bleeding procedure. The cut-in pressure should remain constant since it is unaffected by the adjustment of the small metal screw.

It is important that a minimum differential pressure of 7 psi or more is maintained between the cut-in and cut-out pressure settings to avoid "chattering" of the pressure switch contacts. Differential pressure is defined as the difference between the cut-in and cut-out pressure. Below 7 psi, chattering of the pressure switch contacts may occur as the pressure approaches the cut-out pressure. This will cause the compressor to cycle on and off rapidly which may damage the compressor motor.

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What is the difference between an accelerator used with a Model D dry valve and an accelerator used with the DDX-LP Low Pressure Dry System?

There is no difference in the accelerator model used with either the Model D dry valve or the DDX-LP. Both dry systems use the Reliable Model B-1 accelerator when a quick opening device is needed. However, the trim associated with the accelerator for each system is different, as well as where the air pressure is directed from the outlet of the accelerator. When used with a Model D dry valve, air pressure flowing through the accelerator is directed into the intermediate chamber of the dry valve. Pressurizing this chamber destroys the differential between the air side and the water side of the clapper, causing the dry valve to trip faster. On a DDX-LP system, the accelerator is mounted on the valve trim near the low-pressure actuator and the accelerator outlet piping is open to atmosphere. Since the DDX-LP system utilizes a hydraulically operated valve, the actuator is the releasing device for this system. The faster the air pressure is removed off the air side of the actuator, the faster the DDX-LP system valve trips. Therefore, when the accelerator operates, it exhausts the air pressure off the air side of the actuator to atmosphere, causing the valve to trip faster. Therefore, there is less trim associated with the accelerator trim kit for the DDX-LP than the accelerator trim kit used for the Model D dry valve.

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Are air compressors required to be UL Listed or FM Approved?

No, compressors are not required to be listed/approved. They only need to have enough capacity (hp) to replace the operating air pressure in dry-pipe and double interlock preaction systems within 30 minutes. However, the device used to automatically regulate the air pressure in a sprinkler system must be listed/approved. Hence, a pressure maintenance device must be used. The pressure switch on an automatic air compressor does not qualify as an appropriate means of automatically regulating air pressure in sprinkler system piping.

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Special Hazards / Special Systems

  1. What does "Double-Interlock" mean?
  2. Why does Reliable use the Potter PFC 4410 Releasing Panel in the PrePak?
  3. How do you properly size an air compressor for a dry pipe sprinkler system as well as for a double interlock preaction system?
  4. What is the air pressure requirement for single interlock preaction systems?
  5. Should the trim for a dry pipe system be black steel or galvanized?
  6. What is the difference between the Model A-2 and Model B-1 Pressure Maintenance Devices?
  7. What type of solenoid valve is used on Reliable electric actuated deluge and preaction systems?
  8. What is the difference between single and double interlock preaction systems?
  9. What is the difference between a Reliable Type D double interlock preaction system and a Type F double interlock preaction system?

What does "Double-Interlock" mean?

Double Interlock describes a type of Preaction systems that requires two events to occur before the deluge valve will open and allow water to flow into the sprinkler piping. A good analogy is a door with two locks. You must open both locks before the door will open. Double Interlock Preaction Systems are not a "true" Preaction system. Double Interlock Preaction Systems were developed for freezers and refrigerated warehouses; however, they are often specified for computer rooms. Some approval authorities limit their use to freezers and refrigerated warehouses.

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Why does Reliable use the Potter PFC 4410 Releasing Panel in the PrePak?

The Potter PFC 4410 allows our customers to change the Preaction system from Single Interlock to Double Interlock by a simple programming change. No wiring or piping changes are required.

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How do you properly size an air compressor for a dry pipe sprinkler system as well as for a double interlock preaction system?

NFPA 13 states that a compressor must have a capacity capable of restoring the required system pressure within 30 minutes, except for refrigerated spaces maintained below -5°F, in which case the time requirement becomes 60 minutes. To properly size the compressor to meet these requirements, one must calculate the volume or capacity of the entire sprinkler piping system in cubic feet. Once this is known, the horsepower of the compressor may be chosen based on the cubic feet per minute of compressed air it provides. To determine the volume limitations stipulated by NFPA 13 for these systems, the total piping volume must be converted from cubic feet to gallons (1 ft³ = 7.48 gal.).

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What is the air pressure requirement for single interlock preaction systems?

NFPA 13 requires that sprinkler piping and fire detection devices for preaction systems must be automatically supervised where there are more than 20 sprinklers on the system. The air pressure is only provided to ensure the overall integrity of the piping system. NFPA makes no stipulation for minimum air pressure requirements for single interlock preaction systems for two reasons:

  1. Since a single interlock preaction system is considered a "wet" system, there will be adequate water pressure at the sprinkler to ensure proper sprinkler operation.
  2. The loss of pressurized air does not take part in the operation of the deluge valve.

Therefore, low air pressures, as little as 2 psi, may be used for sprinkler piping supervision. This can be accomplished through the use of the Reliable Model B Air Compressor Panel, or, where a source of pressurized air is provided, with the Model C Air Maintenance Device.

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Should the trim for a dry pipe system be black steel or galvanized?

Reliable offers both black steel and galvanized trim styles for use with our dry pipe valve trims. However, the installing contractor needs to be aware the galvanized trim is a requirement in those jurisdictions following The National Fire Alarm Code NFPA 72 (1991 or 1993 editions, section 5-7.2, and NFPA 72, 1990 edition and earlier, section 3-4.1.2) regarding water-flow alarm initiating devices (pressure switches). This section requires that "piping between the sprinkler system and a pressure actuated alarm-initiating device shall be galvanized or of nonferrous metal or other approved corrosion-resistant material of not less than 3/8" nominal pipe size." This is not a concern with our Model LDX Dry Pipe Valve Systems since the LDX trim only comes in galvanized. However, if just a water motor gong is used, black steel trim is permitted.

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What is the difference between the Model A-2 and Model B-1 Pressure Maintenance Devices?

The Model B-1 Pressure Maintenance Device is used where a small tankless air compressor with no start/stop pressure switch is provided. By wiring the compressor motor to the electrical pressure switch of the Reliable Model B-1 Pressure Maintenance Device, the compressor is controlled by the pressure in the dry pipe valve or deluge dry pilot system. The adjustable pressure range for the Model B-1 is 14 to 60 psi. The Model A-2 Pressure Maintenance Device is designed for use where a controlled source of compressed air or nitrogen is available, such as compressors and tank-mounted compressors that have their own start/stop pressure switch. The Model A-2 will maintain a constant pressure in the system regardless of pressure fluctuations in the compressed air or nitrogen source. The adjustable pressure range for the Model A-2 is 5 to 50 psi.

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What type of solenoid valve is used on Reliable electric actuated deluge and preaction systems?

Reliable uses a solenoid valve manufactured by Skinner, a division of Parker Hannifin Corp. It is a 24VDC normally closed, pilot operated solenoid valve, which requires a .41 amp holding current and 10 watts power. The Skinner P/N is 73218BN4UNLVN0C111C2.

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What is the difference between single and double interlock preaction systems?

Definiton of interlock - to lock together; to connect so that the motion or operation of any part is constrained by another.

Preaction systems are interlocked systems that require a supplemental detection system in the same area as the sprinkler system. Operation of the deluge (preaction) valve is dependent upon activation of a detector, or both a detector and a sprinkler.

Single interlock preaction systems require that only a detector operate to cause the deluge valve to trip. Once the valve trips, water fills the system piping. Water will not be discharged until a sprinkler operates due to the heat of the fire. Given that water is present at the sprinkler at the time of sprinkler operation, single interlock preaction systems are treated as wet systems from a design standpoint.

Double interlock preaction systems require that both a detector AND a sprinkler operate before causing the valve to trip. A good analogy is a door with two locks. You must open both locks before the door will open. Once the valve trips, water will flow into the system piping and discharge immediately out of the open sprinkler(s). Given that the water is back at the valve at the time the sprinkler operates, double interlock preaction systems are treated as dry-pipe systems from a design standpoint, and all of the rules governing the design of dry-pipe systems must be applied to double interlock preaction systems.

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What is the difference between a Reliable Type D double interlock preaction system and a Type F double interlock preaction system?

All double interlock preaction systems require two events to occur before the preaction (deluge) valve actuates: both a detector and a sprinkler must operate before the deluge valve flows water into the sprinkler system piping. Operation of the sprinkler causes the supervisory pneumatic pressure in the system piping to decrease. This decrease in pressure is the second interlock, which causes the preaction valve to trip. The difference between these two types of double interlock preaction systems is based on the method of detecting the decrease in pneumatic pressure. For the Type D system, the device that senses this decrease is a pressure switch installed on the pneumatic supply trim piping. When the pressure switch activates, it provides a second signal to a cross-zoned releasing panel, causing the releasing circuit to energize the solenoid valve. For a Type F system, a low-pressure pneumatic actuator, which is a mechanical device, opens, causing the push-rod chamber of the deluge valve to depressurize. At this point, the solenoid valve has already opened (energized) due to the activation of the detection device. For the Type F system, the releasing panel does not have to be configured for cross-zoned operation. Type F systems are recommended for freezer protection.

Type D systems are commonly referred to as electric/electric-pneumatic type systems, while Type F systems are referred to as electric/pneumatic type systems. To provide a low air supervisory signal, rather than an alarm signal, upon loss of air only for Type D double interlock preaction systems, the Potter PFC 4410 RC releasing panel must be used. For Type F systems, either the RP1001 panel or the Potter PFC 4410RC panel may be used. Utilizing a RP1001 panel with a Type D double interlock preaction system will cause an alarm condition upon loss of supervisory air only. This is because the releasing panel is in cross-zoned mode and the pressure switch is tied into an initiating circuit, which is an alarm circuit.

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