In my last blog I outlined what a TGMS is and items that need to be considered when planning your TGMS service and maintenance plan. In this blog I will help you develop the procedures and maintenance program components required for a complete and comprehensive service and maintenance plan.
The next component of a TGMS maintenance plan is Document Control. The standard associated with this requirement is NFPA 72- 14.2.5.
Maintaining comprehensive, and updated documentation of both the system design as well as all modifications, scheduled maintenance, sensor replacements, tape changes and system testing will allow you to demonstrate compliance should an issue arise with a regulatory agency.
Keeping these documents in a central, secure location will ensure that they cannot be modified by unauthorized personnel. It will also provide the necessary access should it be needed for repairs or modifications in the future.
Some examples of documents that should be maintained include:
This generally starts with a simple visual inspection which is exactly what it sounds like. Using the Plan View drawings and other system information, each device on the system should be inspected visually to ensure that there are no obvious issues.
Depending on the type of device, this may include:
The standard associated with this requirement is NFPA 72-table 14.4.3.2
This involves a functional check of each device and its connection to the central control system whether that is a PLC or SCADA system. Testing outputs like the Gas Alarms Notification devices (horns and strobes) or gas shutdown devices as well as inputs such as from a fire alarm system.
Filters require replacement after about 3-6 months depending on the environment. A cleanroom environment may allow for longer intervals between replacements.
Chemical tapes are constantly moving. They are considered a consumable item and need to be replaced periodically. Chemical tapes need to be stored properly and because of this, generally ordered on a “just in time” basis.
For systems that utilize electrochemical sensor technology, these sensors typically have an operational life of 2-3 years after which they become ineffective and require replacement.
Replacement sensors are ordered on a “just-in-time” basis due to their limited shelf life. Proper planning is necessary to ensure that the needed replacement parts are on hand when scheduling the shutdowns necessary for replacement to minimize downtime.
Replacement sensors typically come with a factory calibration, but a bump-test is typically performed to test operation before putting the TGMS back into operation.
Occasionally changes to the functionality of the system may be necessary. It is important to allow enough time for modifications to be made and for the necessary commissioning and validation. Some of these changes might include:
All electrochemical sensors need to be gas challenged upon initial installation and periodically thereafter. Sensors are challenged, or “bump tested” every 6 months to ensure they are operating properly.
Testing involves specialized knowledge and equipment, and calibrated cylinders of the target gases. This work is typically performed by an outside contractor.
A comprehensive TGMS maintenance plan ensures that the life safety system is functioning properly and protecting the people working in your facility. Given the nature and the limited operational life of critical components, it is crucial to have a plan and to execute it reliably and timely.
Please don't hesitate to contact my via email, vcalio@hallam-ics.com with any questions you might have or contact our Help Desk by clicking the button below.
About the author
Vin Calio is the Regional Manager, South New England. He is an Electrical Engineer with over 15 years of experience in automation and control systems.
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About Hallam-ICS
Hallam-ICS is an engineering and automation company that designs MEP systems for facilities and plants, engineers control and automation solutions, and ensures safety and regulatory compliance through arc flash studies, commissioning, and validation. Our offices are located in Massachusetts, Connecticut, New York, Vermont and North Carolina and our projects take us world-wide.