General Monitors FL4000H Multi-Spectrum IR Flame Detector

Overview

The General Monitors FL4000H is a multi-spectrum infrared flame detector designed by General Monitors, the fixed gas and flame detection design centre of MSA Safety in Lake Forest, California. The manufacturer describes it as an advanced detector that combines superior false alarm immunity with a wide field of view. It uses a multi-spectrum infrared (MSIR) sensor array together with a Neural Network Technology (NNT) discrimination system, and it is built for hydrocarbon fires in refineries, gas plants, offshore platforms and other hazardous areas where a missed fire or a false trip are both expensive.

Seven Star LLC supplies the General Monitors FL4000H, its mounting bracket and its TL105 test lamp to oil and gas operators, EPC contractors and fire and gas integrators in the Sultanate of Oman and across the GCC, with engineering support in Muscat. Many installed fire and gas systems in the region already use this detector, and we support both spares for those sites and new projects.

Measurement Principle

Hydrocarbon flames emit infrared radiation with a characteristic spectral signature and flicker pattern. The General Monitors FL4000H watches the 2 to 5 micron band with several infrared sensors at once, each tuned to a different part of the spectrum. Instead of relying on a fixed threshold or a simple ratio, the NNT algorithm classifies the combined signals from the sensor array as fire or non-fire. According to the datasheet, this MSIR and NNT combination is highly immune to false alarms caused by lightning, arc welding, hot objects and other radiation sources.

The General Monitors FL4000H is designed to detect fires produced by alcohol, n-heptane, gasoline, jet fuels and other hydrocarbons, and it can see through dense smoke produced by diesel, rubber, plastics, lube oil and crude oil fires. Maximum range is 230 ft (70 m) for a 1 sq ft n-heptane fire at high sensitivity, and the typical response time is 10 seconds or less. To keep that performance in the field, the Continuous Optical Path Monitoring (COPM) self-test checks the optical path, including window cleanliness, and the electronic circuitry every two minutes and signals a fault if the view is obstructed.

Engineering Design of the General Monitors FL4000H

The electronics of the General Monitors FL4000H are housed in a 316 stainless steel explosion-proof enclosure 4.3 in (109 mm) high, with a 5.4 in (137 mm) base and a 3.5 in (89 mm) optical housing, weighing 7.9 lb (3.6 kg). Two 3/4 in NPT cable entries are provided and the unit is installed on a stainless steel mounting bracket that allows it to be aimed at the hazard. Hazardous area classifications include Class I, Div 1, Groups B, C, D, Ex d IIC T5 Gb and Ex tb IIIC T100 °C Db with IP66/67 protection.

Outputs are flexible. The General Monitors FL4000H provides a 0–20 mA stepped analog signal, or 3.5–20 mA with HART, in which specific current levels indicate fault, test, optics fault, ready, warning and alarm states. Optional warning, alarm and fault relays are rated 8 A at 250 VAC or 30 VDC, and dual RS-485 ports with Modbus RTU allow up to 128 units, or 247 with repeaters, to be linked to a host. Sensitivity, alarm delay and relay latching are selectable, and an event log stores history for stand-alone diagnostics. A test mode with the test lamp lets technicians check all outputs.

Key Features

The features of the General Monitors FL4000H listed in the datasheet are:

• A multi-spectrum IR sensor array that provides increased range and a wide field of view of 100° at 100 ft and 90° at 210 ft.
• Neural Network Technology that offers superior immunity to false alarms from lightning, arc welding and hot objects.
• Continuous Optical Path Monitoring that checks window cleanliness and electronics every two minutes.
• Multiple communication outputs, including stepped 0–20 mA, HART 6, dual Modbus RTU and warning, alarm and fault relays.
• Selectable high, medium or low sensitivity and an alarm time delay of up to 14 seconds by dip switches or 30 seconds by Modbus.
• Event logging that serves as a stand-alone diagnostic tool.
• A test mode, used with the test lamp, that checks all outputs without a real fire.
• SIL 3 suitability (FM) and approvals including CSA, FM, ULC, ATEX, IECEx, EN 54-10, MED and DNV-GL.

Industrial Applications

For the General Monitors FL4000H, the datasheet lists aircraft hangars, chemical plants, compressor stations, drilling and production platforms, electrostatic paint spray booths, fuel loading facilities, gas turbines, LNG and LPG processing and storage facilities, and refineries as typical applications. In Oman these match the gas processing and compression plants of the interior, oil production stations and gathering facilities, the refinery and petrochemical complexes in Sohar and Duqm, the LNG trains at Sur, airport fuel farms, and power plant gas turbine enclosures. Its smoke penetration makes the General Monitors FL4000H a sound choice where crude oil, diesel or lube oil fires would produce heavy smoke.

Seven Star LLC supplies the General Monitors FL4000H for new fire and gas systems and for like-for-like replacement on existing sites. MSA now also offers the General Monitors FL5000 MSIR Flame Detector as a newer multi-spectrum design, and the same sites often use the General Monitors TG5000 Toxic and Combustible Gas Monitor and the GENERAL MONITORS IR5500 Open Path Infrared Gas Detector for gas detection.

Technical Specifications

The following data for the General Monitors FL4000H is taken from the MSA datasheet attached on this page.

How to Order

For a quotation on the General Monitors FL4000H, send Seven Star LLC the required configuration code or output options and the number of detectors. Our Muscat team will confirm the configuration, share the attached datasheet and support delivery to sites in Oman and across the GCC.