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Natural Ventilation Control Systems

Blue River Controls manufacture a ventilation control system that accurately monitors room or zone conditions and modulates air volume control dampers to maintain the desired comfort conditions. It can be stand alone or linked to a Building Energy Management system.

Both temperature and CO2 are typically be monitored. More sophisticated strategies however can include wind speed, rain and outside temperature sensors. For real world control classroom overrides can also be provided bringing an element of user control which include temporary “on demand” boost facilities.

Flexible programming is designed into this unit to allow full functionality to meet any standard or special requirements. As a general purpose control system it can incorporate control of heating, lighting, security or other functions.

The Ventilation Network Controller is based on a powerful programmable logic controller (PLC) which communicates with a network of input / output (I/O) modules. This allows a large system to be controlled from a central point whilst using a minimum amount of cabling. In essence a central controller operates with distributed inputs and outputs.

The central controller has a user interface (HMI) to facilitate operation by the user or client.

A range of HMIs is available from simple keyboard displays to touch screen graphic terminals.

Various I/O modules are available for use on the network but the 5AI / 2AO analogue module is the most frequently used module for ventilation systems.

If more inputs and outputs are required multiple I/O units can be used. Up to 96 analogue inputs can be accommodated on a single loop system.

For larger systems multiple loops can be used. The system is programmed via a laptop computer using standard Mitsubishi soſtware. A Modbus interface is available so that information can be passed to a Building Management System for monitoring purposes.

HM Prison Smoke Control Project

Blue River Controls were recently award a contract to provide a smoke control system for a prison in Northern Ireland.

The smoke control system was manufactured at company’s factory near Aylesbury and then installed in the new high security 360-cell wing of the prison.

A total of 1300 motorised smoke dampers are operated by Blue River Control’s damper control modules. These are connected to a centralised control panel via a fire detection analogue addressable protocol that complies with BS5839.  The system is divided into 16 addressable loops which are interrogated from a single touch screen graphics display.

The company’s product quality was a key selection criteria and along with the performance of previous contracts with the primary Mechanical & Electrical Contractor for the prison.

University College Hospital London

University College Hospital, London had a 12-storey building requiring a new smoke control system to bring it up to date with safety regulations. Some of the lower floors had motorised smoke dampers and control systems installed but there were problems. The old control system was not reliable. Faults with control communications resulted in dampers loudly slamming shut for no reason causing a nuisance to hospital occupants. A newer system from the same manufacturer on the third floor also had issues and the hospital had lost confidence that either system would operate correctly in a fire.

The existing motorised smoke dampers were serviceable but the manufacturer claimed that they could not be reused with their updated control system. Hence a completely new set of motorised dampers and control system was necessary, a very expensive exercise. Unconvinced, the hospital sought specialist advice from Blue River Controls to propose a more flexible, cost effective solution.

Blue River Controls proposed a solution with new control system panels in each floor’s stairwell lobby and new communications cabling to the existing motorised dampers retrofitted with new control modules. The solution also had to conform to the hospital’s fire alarm (BS5839) standards and safety regulations.

The hospital trust adopted a phased approach and initially trialled Blue River Systems in a new area of the hospital to prove system reliability and build confidence. Blue River partnered with the hospital and trained their engineers to install and commission each damper control unit to reduce costs. Blue River engineers were only required to download the software to each panel’s Programmable Logic Controller and commission them with a rigorous test sequence.

On the fascia of each control panel there is a display where tri-colour indicators show the status of individual dampers allowing hospital engineers to monitor the system at a glance. The panels are also provided with fireman’s override switches and a keyboard display for maintenance.

The initial trial was followed by the very successful upgrade of the lower floors and Blue River were given the go ahead to install systems in the rest of the hospital.

A professional handover with hospital engineers enabled them to fully maintain the system without further assistance. Additionally, use of a Mitsubishi Programmable Logic Controller in each control panel ensures flexibility and software maintainability should change be required in the future.