Case Studies | RCF Automation

Case Studies

Real
Results.

See how RCF delivered innovation and solved challenges with
excellence.

Changes in the Supply Air Controls to Reduce Alarms

One of the Life Safety Systems maintained by RCF Automation monitors multiple exhaust and air supply systems in 25 laboratories and common areas in a research facility. This Life Safety System uses a combination of different sensors to determine the condition of each exhaust system and supply air system. This highly automated system uses a powerful SCADA as an interface with the users and data logging.

Project Background

In 2022 RCF Automation was engaged to support the customer in the modification of some complex controls with the intent to reduce the occurrence of alarms. RCF Automation helped in the organization and analysis of the data acquired by the SCADA system and in the evaluation of the requirements for each area. Any change proposed should ensure that the safety and operational requirements for all equipment in the area are respected:

• Minimum fresh air exchanges per hour for the area.
• Minimum exhaust requirements for all exhaust systems.
• Face velocity and air exchanges for fume cupboards.
• Room pressure fluctuations within acceptable range considering all equipment in the room: glove box, desiccator, ventilated cabinets, dangerous goods cabinets, etc.

The data acquired by the SCADA was carefully analysed and showed that part of the controls implemented by a third party were causing excessive fluctuations in the airflow and consequently, in the pressure in specific areas. This condition was causing multiple pieces of equipment to alarm and trigger local evaluation of research laboratories. These alarms were deemed genuine alarms, as the cause of the problem was a lack of airflow or excessive pressure in the room for extended periods.

The following chart shows the Air Handling Unit (AHU) control before and after the Building Management System (BMS) changes. Before the changes, the Variable Speed Drive (VSD) was dynamically controlled to keep the laboratory pressure and supply airflow within range. However, this control caused elevated levels of fluctuation in the room’s condition, placing part of the equipment in the room to operate outside its optimal range, and in some cases, outside the safety ranges, which caused alarms and evacuations.

Each individual area was assessed and its supply air VSD was set to a fixed speed that ensures pressure and airflow meet design requirements but allows them to fluctuate as the room’s condition changes (doors, fume cupboards etc). Comprehensive tests were performed considering optimal cases and worst-case scenarios, so each area was tuned to ensure that regardless of the state of variable exhaust loads, doors or other possible interferences, all equipment remained operating within its optimal range.

Results

Two weeks after the work was finalized, it was found that the new controls, along with other improvements made to the system, reduced significantly the number of alarms and evacuations. The three main indicators of this improvement are explained below:

Quantity of alarms registered by the Life Safety System reduced by 93%. This indicator considers the number of times a sensor or module entered an alarm condition. It is important to note that each of these alarms are genuine events of abnormal conditions registered by the Life Safety System. These genuine events are managed by controls that do not necessarily trigger an evacuation of an area, they rather stop local processes when necessary.

Quantity of distinct devices and modules generating alarms reduced by 95%. This indicator considers the number of different devices or systems entering an alarm. Reducing this number allows the response team to focus on individual occurrences faster instead of having to filter between multiple sources to determine the case-consequence relationship for an event. After the simplification was implemented, only 14 sensors presented alarms in the analysed period.

Quantity of requests for support from security reduced by 40%. This indicator shows how many abnormal conditions have triggered a request for support from the security team. These are genuine evacuations of specific areas within the research facility.

The simplification implemented reduced the number of alarms and potential evacuations by 93%. It had a huge impact on the operational time for the affected laboratories. Additionally, this work allowed more modules to be enabled within the Life Safety System as the root cause for excessive alarms was identified and dealt with.