FAQs - Fire Suppression Trays (Rackmount)

There are two types of detection system and these dictate where they should be installed in a server cabinet.

Standard Point Detection: for this type, the Redetec system should be installed in to the top 2U of each of the racks to be protected. A further 2U of additional free space should be allocated below the unit (giving 4U Total). If the Redetec unit is to be mounted at any other point in a server cabinet (i.e., not below the midpoint) or without the additional 2U of free space below the unit, then additional remote detection will be required.

High Sensitivity Smoke Detection: for this type of installation, it is recommended, that the Redetec is installed in to the top 2U of each of the racks to be protected. Note it is not recommended, to mount the Redetec unit below the mid-point of any server rack.

The Redetec unit triggers as soon as the smoke detector(s) sense the presence of smoke. As a default, Redetec units are set to ‘double-knock’ but can be set for a ‘single-knock’ event. Once smoke is detected, the extinguishing agent (either FK-5-1-12 or HFC227e) releases over a period of approximately 9 seconds.
The Redetec unit has a 10 second delay between confirmed alarm and extinguishing agent release but this can be easily changed to either 1, 5, 10, 15, 30 or 120 seconds.

The HFC227ea and FK-5-1-12 extinguishing agents are non-conductive, non-corrosive and leave no residue on discharge. Therefore they do not affect equipment with in a server rack or data cabinet.

The Redetec units are fully serviceable and can be refurbished at the factory, with cylinders recharged with a new extinguishing agent. New replacement cylinders and actuators are held in stock for a quick turn-around in the field if required. Factory trained engineers can also swap cylinders on site for clients with maintenance contracts or requiring an emergency site visit.

There is 1.2Kgs of either HFC227ea or FK-5-1-12 in each cylinder. There is one cylinder onboard the Redetec for protecting up to 1.5m³ and two cylinders in the Redetec units for protecting up to 3.0m³.

A Redetec tray with Point Detection is rated at 8W (27.32 BTU) i.e. PF/RED/1.5-3.0 & PN/RED/1.5-3.0. A Redetec with HSSD is rated at 11.48W (39.17 BTU) i.e. VF/RED/1.5-3.0 & VN/RED/1.5-3.0

All Redetec units have 2x 1.2Ah 5 year design life sealed lead acid batteries built-in to provide up to 12hrs battery backup for a unit with standard detection. The battery provides protection from mains power supply failure but we would also recommend that the device is powered from an uninterruptible power supply for additional power protection. The battery is inspected during a preventative maintenance visit and will require replacement in years 3-4.

Redetec units have two options for detecting a fire, both of which rely on the detection of smoke. This is primarily because it is important to detect an incident at its very earliest stage, and in some cases before a naked flame is visible. It is possible to have a fire without smoke, though highly unlikely in the IT environments the unit is designed to provide protect for.

A Redetec unit as standard has volt free contacts for 1st Stage Fire (Pre-alarm), 2nd Stage Fire (Confirmed alarm) & Fault condition which can easily be connected to a BMS system or Intelligent UPS and/or the main building Fire Alarm System to give the earliest possible warning of an incident.

The Redetec system is set to ‘double-knock’ as default and can easily set to operate on a ‘single-knock’ basis if required.

There is also an optional IP module to provide remote monitoring over an IP network, sending alerts for 1st Stage Fire (Pre-alarm), 2nd Stage Fire (Confirmed alarm) & Fault conditions to up to three email addresses via SMTP or SNMP, with each unit is fully configurable via a built in Web Server.

For sizing measure the internal volume of the cabinet (WxDxH) in metres. For sizing we do not take into account what equipment is installed in the cabinet as this can change over time. All capacity calculations are based on the cabinet being empty.

For up to 1.5m³ use models: PF/RED/1.5, PN/RED/1.5, VF/RED/1.5 & VN/RED/1.5

For up to 3.0m³ use models PF/RED/3.0, PN/RED/3.0, VF/RED/3.0 & VN/RED/3.0

Example 1: Cabinet dimensions H: 42u/c2.1m x W: 0.6m x D: 0.8m = 1.01m³
Suggested models: PF/RED/1.5, PN/RED/1.5, VF/RED/1.5 or VN/RED/1.5

Example 2: Cabinet dimensions H: 42u/c2.1m x W: 0.8m x D: 1.0m = 1.68m³
Suggested models: PF/RED/3.0, PN/RED/3.0, VF/RED/3.0 or VN/RED/3.0

All Redetec part numbers beginning with ‘P’ use Apollo Optical Point Detection and all models beginning with ‘V’ utilise Airsense HSSD (High Sensitivity Smoke Detection).

The main difference is that HSSD provides phenomenal response to detecting smoke within high airflow environments. HSSD continuously samples air from various points within the cabinet. It is can detect incipient stages of combustion within a server cabinet. With standard detection you would need much more smoke to be generated in order to trigger.

HSSD is typically set to a level 10x more sensitive than the standard detection as default. The typical Sensitivity range of HSSD is 0.03% to 25% obs/m (obscuration per meter). The typical Sensitivity range of Point Detection is 3.5% – 5.0% obs/m (obscuration per meter).

The smoke from the smoldering stage of a fire is typically made up of large combustion particle, between 0.3 and 10.0 µm, and this is what obscures the detector. The sensitivity on an HSSD can be adjusted via a laptop to be more or less sensitive based on the environment. The sensitivity on a Point detector is fixed with no further adjustment.