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Fire Suppression Industries is "An OEM of Protectowire FireSystems"

Digital linear heat detection 
by Protectowire

Standard Digital (PHSC)

The Standard Digital Protectowire Heat Sensitive Cable (PHSC) Linear Heat Detector can best be described as a continuous run of spot heat detectors. It is capable of sensing heat anywhere along its length and initiates an alarm once its fixed activation temperature is reached.

The Standard Digital (PHSC) Linear Heat Detector works in the following manner. Once the ambient temperature meets or exceeds its fixed temperature, the heat sensitive polymer weakens, which in turn allows the twisted spring steel conductors to make contact, which results in an electrical short that triggers an alarm signal.

The Standard Digital (PHSC) Linear Heat Detector is designed to be used on a compatible fire alarm control module or panel.

All Protectowire Linear Heat Detectors must be installed in accordance with applicable sections of NFPA 72 or as required by the local AHJ.

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Unique advantages of Protectowire Linear Heat Detectors include:

  • Detects heat at any point along its length

  • Low maintenance

  • Outer jackets resist corrosion, chemicals, moisture, and extreme temperatures

  • Can be installed close to hazards to provide rapid response

  • Long service life

  • What is the primary difference between Protectowire PHSC and PLR Digital Linear Heat Detectors?

Protectowire PHSC series is manufactured using spring steel conductors, while the PLR series is manufactured with low resistance tri-metallic conductors that are engineered to enable longer detector zone lengths on other manufacturers' control equipment. The amount of Protectowire (PHSC or PLR series) that can be installed on another manufacturers' control equipment is directly determined by the maximum loop resistance of the equipment’s initiating device circuit. Protectowire’s PHSC digital linear heat detectors have an approximate resistance of 0.185 Ohms per foot (0.607 Ohm per Meter). Protectowire’s PLR digital linear heat detectors have an approximate resistance of 0.058 Ohms per foot (0.191 Ohm per Meter). The PLR series detectors allow for approximately 3x longer lengths on the same initiating device circuit.

  • Can Protectowire Linear Heat Detectors with different alarm temperature ratings be installed in the same zone?

Yes. Protectowire offers two series of detectors capable of supporting different activation temperatures on the same series initiating device circuit. This allows a single Protectowire Linear Heat Detector zone to protect multiple areas with different ambient temperatures. The PHSC Series can support 135°F, 155°F, 190°F, 220°F, 280°F and 356°F being spliced into the same initiating device circuit. The PLR Series can support 155°F and 190°F being spliced into the same initiating device circuit.

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Type EPC is designed for interior, commercial, and industrial applications. The Features of this jacket include low moisture absorption, resistance to many common chemicals, and excellent flexibility at low temperatures.

PHSC-155-EPC          Protectowire, Type EPC (155°F / 68°C)

PHSC-155-EPC-M      Protectowire, Type EPC on Msg. Wire

PHSC-172-EPC          Protectowire, Type EPC (172°F / 78°C)

PHSC-172-EPC-M      Protectowire, Type EPC on Msg. Wire

PHSC-190-EPC          Protectowire, Type EPC (190°F / 88°C)

PHSC-190-EPC-M      Protectowire, Type EPC on Msg. Wire

PHSC-220-EPC          Protectowire, Type EPC (220°F / 105°C)

PHSC-220-EPC-M      Protectowire, Type EPC on Msg. Wire

PHSC-280-EPC          Protectowire, Type EPC (280°F / 138°C)

PHSC-280-EPC-M      Protectowire, Type EPC on Msg. Wire

PHSC-356-EPC          Protectowire, Type EPC (356°F / 180°C)

PHSC-356-EPC-M      Protectowire, Type EPC on Msg. Wire


Type XCR consists of a high-performance fluoropolymer jacket and is designed for exterior environments as well as harsh interior applications. Features of this low smoke jacket include excellent chemical resistance, abrasion resistance, weather resistance, and high-temperature performance. XCR is the only detector that is FM-approved for corrosive environments.


PHSC-155-XCR          Protectowire, Type XCR (155°F / 68°C) 

PHSC-155-XCR-M      Protectowire, Type XCR on Msg. Wire

PHSC-172-XCR          Protectowire, Type XCR (172°F / 78°C) 

PHSC-172-XCR-M      Protectowire, Type XCR on Msg. Wire

PHSC-190-XCR          Protectowire, Type XCR (190°F / 88°C) 

PHSC-190-XCR-M      Protectowire, Type XCR on Msg. Wire

PHSC-220-XCR          Protectowire, Type XCR (220°F / 105°C) 

PHSC-220-XCR-M      Protectowire, Type XCR on Msg. Wire

PHSC-280-XCR          Protectowire, Type XCR (280°F / 138°C) 

PHSC-280-XCR-M      Protectowire, Type XCR on Msg. Wire

PHSC-356-XCR          Protectowire, Type XCR (356°F / 180°C) 

PHSC-356-XCR-M      Protectowire, Type XCR on Msg. Wire



Type LSZH consists of a durable low smoke zero halogen outer jacket and is designed for interior commercial and industrial applications. Features of this jacket include low moisture absorption, resistance to many common chemicals, and excellent flexibility at low temperatures. 

PHSC-135-LSZH        Protectowire, Type LSZH (135°F / 57°C)

PHSC-135-LSZH-M    Protectowire, Type LSZH on Msg. Wire

PHSC-155-LSZH        Protectowire, Type LSZH (155°F / 68°C)

PHSC-155-LSZH-M    Protectowire, Type LSZH on Msg. Wire

PHSC-172-LSZH        Protectowire, Type LSZH (172°F / 77°C)

PHSC-172-LSZH-M    Protectowire, Type LSZH on Msg. Wire

PHSC-190-LSZH        Protectowire, Type LSZH (190°F / 88°C)

PHSC-190-LSZH-M    Protectowire, Type LSZH on Msg. Wire

PHSC-220-LSZH        Protectowire, Type LSZH (220°F / 105°C)

PHSC-220-LSZH-M    Protectowire, Type LSZH on Msg. Wire

PHSC-280-LSZH        Protectowire, Type LSZH (280°F / 138°C)

PHSC-280-LSZH-M    Protectowire, Type LSZH on Msg. Wire

PHSC-356-LSZH        Protectowire, Type LSZH (356°F / 180°C)

PHSC-356-LSZH-M    Protectowire, Type LSZH on Msg. Wire


Type XLT consists of a outer jacket that is specifically selected for cold storage and freezers . Features of this jacket include low moisture absorption and excellent performance in extremely low temperatures. This detector has been UL and FM tested to –60°F (–51°C).

PHSC-135-XLT         Protectowire, Type XLT (135°F / 57°C)

PHSC-135-XLT-M     Protectowire, Type XLT on Msg. Wire



Type PLR-EPR consists of a polypropylene elastomer jacket and is designed for universal compatibility through the use of special low-resistance inner conductors. Features of this jacket include good abrasion resistance, chemical resistance, and weather resistance. 


PLR-155R               Protectowire Universal, Type R (155°F / 68°C)

PLR-155R-M           Protectowire Universal, Type R on Msg. Wire

PLR-172R               Protectowire Universal, Type R (172°F / 78°C)

PLR-172R-M           Protectowire Universal, Type R on Msg. Wire

PLR-190R               Protectowire Universal, Type R (190°F / 88°C)

PLR-190R-M           Protectowire Universal, Type R on Msg. Wire



Type PLR - XCR is constructed with low resistance inner conductors, allowing for longer detector zone lengths on most types of fire alarm panels including addressable panels. Utilizing a high-performance fluoropolymer outer jacket, this detector is specifically designed for use in applications where extreme environment and product criteria must be met. The flame retardant, low smoke jacket provides excellent abrasion resistance and mechanical properties over a broad range of applications. It provides excellent chemical and permeation resistance to a wide range of acids, bases, and organic solvents, as well as simple gases. In addition, the jacket exhibits very little change in tensile properties upon outdoor exposure to sunlight and weather.

PLR-500CR            Protectowire Universal, Type CR (500°F/260°C)

PLR-500CR-M        Protectowire Universal, Type CR on Msg. Wire


Types of Digital linear heat detection 

Industries & Applications

Oil & Gas

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Storage tanks, pipelines, offshore platforms, and refineries utilize numerous processes involving flammable liquids and toxic chemicals. Every facet of these processes must be monitored regardless of the hazardous challenges they present. Our product range of customized control panels, specialty detectors, and hazardous area approvals makes Protectowire the leading supplier of Linear Heat Detection Systems for the oil and gas industry.
















Pipelines present unique detection challenges as they may span long distances or consist of densely configured systems within the confines of a processing plant. They often carrying combustibles like oil, gasoline, and LNG/LPG (liquefied natural gas/liquefied petroleum gas) which can leak, causing liquid spills or gaseous emissions that create hazardous concentrations of combustible gasses. Protectowire Linear Heat Detectors can easily be wrapped around pipes, valves, and other vulnerable connections to ensure early detection if a hazardous ignition occurs.

Power Generation

Power generation facilities such as fossil fuel, nuclear, and hydroelectric all represent unique fire hazards and design challenges. Protectowire Linear Heat Detection Systems have been specifically designed to operate successfully in these extremely hostile environments. The rugged reliability of our products has been tried, tested, and proven to be the superior choice for fire detection in the power generation industry.



Cable Trays











Protectowire Linear Heat Detectors can identify the location of an overheat or fire condition anywhere in a cable tray. The detector may be economically applied to monitor each tier of cables and is adaptable to all cable tray types such as a ladder, trough, solid-bottom, channel, cable bus duct, and tubing raceway. In most cases, the detector follows the vertical and horizontal runs and may be placed in direct contact with the cables.



Other Industries include....


Warehousing & Cold Storage

In rack protection and cold storage warehouses with sub-zero storage, temperatures are a few of the challenges found in the warehouse and storage industries. Protectowire Linear Heat Detectors offer innovative specialty products, single-source capabilities, and a total system solution to solve the fire detection challenges associated with this industry.

Barns and Stables

Protectowire is not adversely affected by temperature fluctuations which often occurs between the heated and unheated areas of a barn or stable building. Unlike smoke detectors, other environmental factors such as dust, dirt, and insects do not affect the operation of Protectowire Detectors.

Protectowire Linear Heat Detection Systems may be used to activate a pre-action sprinkler system in addition to providing fire detection capabilities. The systems are designed to provide the most reliable and cost-effective fire detection available for the risks and environmental conditions associated with this unique application.

Cold Storage

Protectowire Confirmed Temperature Initiation (CTI) Series Linear Heat Detectors provide the most dependable and cost-effective fire detection option for cold storage applications. Protectowire FireSystems provides the only Digital Linear Heat Detector that offers short circuit discrimination. Unlike conventional linear heat detectors, damage to the CTI Series Linear Heat Detector will not cause a false alarm. The CTI Series uses multi-criteria detection to eliminate false alarms and assures only heat-activated alarms are reported. Most refrigerated and warehousing facilities are double interlocked pre-action systems, which makes the CTI Series an ideal Linear Heat Detector for this particular type of suppression system.

When used in double interlock pre-action sprinkler systems, Protectowire is typically installed at the ceiling and in the racks at every level of sprinkler piping. The detector has been specifically designed for the harsh environment and can protect in temperatures up to -60°F (-51°C), depending upon the model selected. Protectowire Detectors are available in wide variety of alarm temperatures and jackets suitable for any type of installation environment.

Self Storage units

Protectowire Linear Heat Detectors are ideally suited for use in self-storage warehouses. The detector can be installed longitudinally in each building thereby covering each individual storage compartment. By incorporating a Protectowire FireSystem Control Panel with alarm point location meter, the linear distance of the alarm point can be identified and related to a specific cubicle. Protectowire’s low maintenance requirements allow for a simple system test procedure which eliminates the need to unlock every storage space for inspection and testing of the fire alarm system.


Protectowire Linear Heat Detectors provide a rugged and versatile proximity fire detection option for the transportation industry. With a resistance to a variety of automotive fluids, solvents, and environmental elements, as well as a flexible design, Protectowire is an ideal choice for tight spaces and extended runs. The detector is both vibration and abrasion-resistant which allows it to be placed inside engine compartments. A long service life and easy annual testing means there is minimal downtime or disruptions. Our vast experience across a wide range of applications is why Protectowire is the preferred choice for smart transportation companies.

Airport Industry

The highest risk of fire danger within airport facilities are from fuel storage, cargo materials, and from the aircrafts themselves. Protectowire’s Standard PHSC Linear Heat and CTI Series Detectors both offer minimal maintenance and are not adversely affected by temperature fluctuations making them ideal detectors for the airport industry. When compared to spot-heat and infrared detectors, Protectowire Detectors can greatly reduce installation costs while making annual testing easy and simple.


Car Parks & Parking Garages

Harsh environmental conditions in parking garages or car parks require linear heat detection that can withstand these factors. Protectowire Confirmed Temperature Initiation (CTI) Linear Heat Detector has abrasion resistance, weather resistance, and high-temperature performance necessary to detect a fire condition in garages which could threaten the integrity of the structure.


Protectowire wrapped around or in contact with the escalator bearings warns of overheating before a fire can start.

Marine Vessel Engine Compartments

Protectowire is typically installed in a vessel’s engine room to indicate an overheat condition or to initiate a fire suppression system in the event of an actual fire.

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