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  • Writer's pictureAqua Production Systems

Three Levels of Hatchery Alarm Systems

Part of operating an aquaculture facility is keeping it running through good days, bad days, storm days, and holidays. A common question that arises is what to alarm and how. Similarly, monitoring is often up for discussion at the same time.

The wrong answer is to buy as much alarm and monitoring coverage as possible. Good luck predicting accurately every possible scenario that is going to go wrong! Many customers need to ask the question differently to get a solid answer. Rather than “what should I alarm” ask “what do I want to get out of bed at 3am in a blizzard drive to the site for?”

As in all equipment purchases, there is no single right answer, but there are principles to follow.

The first principle is that there is no alarm system that can replace a conscientious technician. Whomever is tasked with locking up at the end of the day needs to be focused and patient at the end of their shift. If anything appears out of place, it must be investigated and determined to not be a risk to the equipment or the water quality prior to leaving. While staying a few minutes or hours past the end of shift may be a thankless job, it certainly beats coming back in or explaining how you think everything was great when you locked up the night before.

So, what is the primary purpose of an alarm system? Consider that without an alarm system, a 24/7/365 staff presence would be required on site solely for the purpose of monitoring all systems and equipment. The alarm system can be used to reduce this work load on staff.

There are several levels of systems that serve the alarm purpose. Each have their raison d’etre, their pros and their cons.

Level 1 – Alarm-Only

An alarm-only system is a system that notifies staff to a rapid, critical change in the hatchery operation. Most things in a hatchery happen relatively slowly. Fish take weeks to hatch and months to grow. Even if oxygen supply is too low, it may take hours before it becomes a critical situation.

The classic example is a power failure. Whether weather related or simply a texting driver taking out a utility pole, power failures should result in a full and immediate inspection of hatchery systems by staff – no matter the hour. Don’t forget to check that the alarm system is also working.

It is my opinion that a power failure should result in an alarm that can only be turned off by a visit to the site by a technician who is then responsible to check all other systems regardless of their ‘alarm status’. We build redundancy into every part of a hatchery except the alarm system and recently I have heard two stories of alarm system failure related to power outages. Both cases caused significant product losses. Incorporate redundancy into the power failure alarm system and insist on checking every electrical device after each power incident. A ‘post-power loss’ checklist may be called for here. Many motors and other electrical items can suffer damage from full or partial power loss.

The alarm-only system is a robust system but relies on conscientious response to its alarms. Designing a system that does not create responder-fatigue is key to its success. Resist the urge to alarm every point in the place. Put the alarms to the test of ‘what do I want to get out of bed at 2am for’?

Level 2 – Alarm & Monitoring

The second level of alarm system can provide some monitoring capabilities. In recent years, it has become relatively affordable to create a monitoring system that allows anyone to check oxygen and temperature and equipment status from anywhere in the world on a smartphone. While this may provide decision making information, it is not a replacement for eyes on the hatchery floor following an alarm.

The purpose of a monitoring system is to collect information and provide it to the operator(s). This again saves man-hours, but it is not really an ‘alarm’ function. However, from a technical perspective, it is easy to piggy-back an alarm system onto the monitoring system. For this reason, they are often sold and installed together.

Monitoring, itself, has many levels of application. Systems are available to provide current and historical records of oxygen, pH, flow rate, temperature, pump status, and more. The conscientious technician will have due diligence to know what each alarm does and does not mean. For example, does water temperature mean the tank is currently at temperature or that it the water in a certain pipe is at the desired temperature? Does the pump status refer to the position of the on/off switch or does it indicate that there is flow in the pump discharge pipe?

The alarm and monitoring system requires the operator to be aware of its dual purpose – alarms in case of rapid changes, and the ability to monitor current and past parameters. Remember, it does not (usually) predict the future. The operator must be aware of what the alarm means and in most cases an alarm should be responded to by visually checking the component and system in question.

Level 3 – Alarm & Monitoring & Controls

The third level of alarm system incorporates some interactive control capability. The dual purposes of alarm notification and monitoring are now joined with the ability to provide some automatic and/or remote response to water quality parameters. Remote, meaning, not by a technician standing at the tank itself, but from the central computer system, or through the central control system, online perhaps.

Incorporating controls into a monitoring system requires putting a great deal of faith (“faith being the evidence of things not seen”) into both the control system and the personnel who operate it. Again, the operator is going to need to be intimately familiar with the system and what each parameter actually means.

What are you confident enough to adjust from a remote station? In theory, we are naturally askance at this idea. In practice, we do it all the time. We set thermostats for example in our home or hatchery and then walk away with confidence that the thermostat will control the temperature. Perhaps, a more extensive control system can be successful given enough familiarity with the system.

Again, the principles outlined in the most basic system cannot be forgotten. The conscientious operator has to translate and verify the information given by the alarm, monitoring, and control systems. The power failure alarm should still be responded to by a physical set of eyes. The most involved system in the world, is still a mechanical system, and therefore prone to mechanical limitations such as corrosion, fouling, power failure, cell reception, and phone line uptime.

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