Remote-controlled firefighting

Automated firefighting is in growing demand and technical developments in drive engineering, sensor technology and control technology are unlocking future potential in this field.

In particular, remote-controlled monitors in combination with automated fire detection systems allow for targeted firefighting operations.

Advantages

The most common automated firefighting systems are sprinkler systems and spray nozzles. Automated firefighting systems with remote-controlled monitors are used for fire protection in a number of areas, such as:

• Tank farms for refineries
• Petroleum loading terminals
• Aircraft hangars
• Thermal power plants
• Production facilities
• Recycling plants
• Waste incineration plants

A range of monitors and mountable nozzles are available and offer the potential for flexibility and more effective fire protection for high risk areas. Remote-controlled monitors allow for targeted firefighting operations in confined spaces and can be used for extinguishing agents like water, low-expansion foam and powder. The nozzles are designed to suit the specific type of extinguishing agent.

The aim of automated firefighting systems and remote-controlled monitors is to provide fire detection, control and protection using a minimum number of firefighting personnel.

The use of programmable logic control (PLC) systems and communication facilities may further unlock the potential offered by remote-controlled monitors. A PLC system allows for connection between automatic fire detection systems and fire alarm control panels, which may be especially useful for large and complex facilities and may also potentially improve the speed of response times and subsequent effectiveness of firefighting interventions.

Design Requirements

Specific design and construction parameters are required for remote-controlled monitors when used in automated firefighting systems.

These requirements include:

• Zero-clearance bearings – aimed at preventing tilting of the pivot mounting, to achieve repetition accuracy for pre-programmed extinguishing operations
• Reduced water jet repulsion - decreasing the power needed to swivel the monitor
• Contact-free and wear-free absolute encoders - for high repetition accuracy and accurate nozzle direction
• Sensors - to monitor movements and positions even without electricity
• Fitted hand wheels – for manual manipulation of the monitor, which may be required during maintenance or commissioning. This ensures that no reference adjustment is necessary for recalibration of the programmed automated swivelling movements.
• Absolute encoders fitted to the drives to regulate the spray pattern - allows shape and range of the spray target area to be modified
• Larger spraying angle - reduces the impact of the extinguishing agent spray-jet and potentially prevent a bulk-materials fire from spreading
• Wide swivelling ranges – preferably a horizontal swivelling range of 360° and vertical swivelling range of 90º to -90°, with both swivelling axes fitted with self-locking worm gears to prevent unintended adjustment of the monitor
• Self-locking gears - to hold remote-controlled monitors in a desired position without the need for additional brakes
• Components made of seawater-resistant cast aluminium and anodized coating – aimed at improving corrosion resistance
• The use of cast parts – aimed at reducing the risk of stress corrosion cracking and increasing the design flexibility and optimisation process
• The use of computational fluid dynamics (CFD) simulation software – aimed at ensuring that the components can be flow-optimised
• A long nozzle design – to reduce turbulence from the pivot mounting and increase the reach of CFD flow-optimised nozzles
• The optional use of regulators fitted to nozzles for remote-controlled monitors – to regulate the flow rate of the extinguishing agent

Control Systems

A number of different control systems can be used in automated fixed firefighting systems with remote controlled monitors. These range from standalone control systems for a single monitor, to complex systems for multiple monitors, with decentralised individual controls connected to a central control unit through a fibre-optic network.

It is recommended that the control system should include automatic self-testing, where the functionality of all drives and sensors on the remote-controlled monitors is tested. If a component fault is detected, an error message is sent to a monitoring centre so that a potential malfunction may be averted. This aims to increase the reliability and availability of the automated firefighting system.

In addition, the automated control systems are fitted with a human-machine interface option in order to facilitate the commissioning of the system. This allows for threshold values to be adjusted in the control cabinet, reducing the need for setting changes to be made directly at the remote-controlled monitors.

Oscillation modes can also be individually selected and programmed for single or multiple monitors. Four different oscillating modes are available and are selected according to the requirements of the specific application. This allows potentially hazardous areas to be separated into individual zones where one or more monitors will be activated in case of an alarm.

If control systems are interconnected with fire detection systems such as infrared cameras, the monitor will automatically swivel to an area identified by the fire detection system and direct the extinguishing operation to the source of the fire. This may be especially effective in locally confined, initial fires.

Future potential

The technical developments in the field of drive engineering, sensor technology and control technology offer a wide scope for the future potential of fire detecting and firefighting.

The use of monitors further improves the potential for effective, localised firefighting with a focus on conserving resources as much as possible.    

Germany-based company FireDos and its South African partner Dosetech, states that it uses the latest technology in the design and development of its monitors, to offer a number of potential advantages in the firefighting arena.