By Dr. Nadia Sabeh, Founder/President of Dr. Greenhouse
Controlling the environmental parameters of the indoor farm is essential to managing the productivity and health of your crop.
This presentation will discuss the critical roles that VPD, airflow, CO2, and other parameters play in the dynamic indoor environment, and we will review different systems and strategies you can use to manage them.
A project case study will be presented to demonstrate the costs associated with different climate management (HVAC) alternatives, including first cost, operating cost, maintenance, and crop productivity.
The outside environment can vary widely depending on where your facility is located. However, the internal environment around any activity can have an effect on that activity and any personnel performing the activity, whether that’s storage, manufacturing, testing, office work, etc. These effects can, in turn, affect the product of such activities. Environmental control strategies aim to ensure that the environment supports efforts to keep product quality high in a manner that is economical and sensible, regardless of the outside weather conditions.
For this article, let us define the “environment” as characteristics related to the room air in which an activity is performed, setting aside construction and procedural conditions that may also affect the activity. Also, let us leave the issue of managing toxins or potent compounds for another time (as well as lighting, noise, vibration, air flow, differential pressures, etc). The intent here is to focus on the basics: temperature, humidity and a little bit on particulate counts.
Temperature and humidity are key because a non-suitable environment can result in the following problems:
Increased operator error
Difficulty in managing products (e.g. powders, capsules, etc)
Degradation of raw materials
Microbial and mold growth
USP <659> “Packaging and Storage Requirements” identifies room temperature as 20-25°C (68-77 °F) and is often used as a guideline for operations. If gowning is required, the temperature may be reduced to improve operator comfort. This is a good guide for human working areas. For areas that require other specific temperatures (e.g. refrigerated storage for raw materials), the temperature of the area should be set to those requirements.
Humidity can affect activities at the high end by allowing mold growth and at the low end by increasing static. Some products (or packaging materials) are hydroscopic, and will take on water from a humid environment. Working with particular products (e.g. powders) can also drive the requirement for better humidity control, since some powders become difficult to manage in either high or low humidity environments. For human operations without other constraints, a typical range for desirable humidity is in the range of 20 to 70% RH in manufacturing areas, allowing for occasional excursions above. As in the case of temperature, other requirements may dictate a different range.
In a typical work environment, it is often sufficient to control the temperature, while allowing the relative humidity to vary. If the humidity does not exceed the limits for the activity, then this approach is preferred, because controlling humidity adds a level of complexity (and cost) to the air handling. If humidity control is required, it can be managed by adding moisture via various humidification systems, or cooling/reheating air to remove moisture. When very low humidity is required, special equipment such as a desiccant system may be required. It should be noted that although you can save money by not implementing humidity control at the beginning, retrofitting your system for humidity control at a later time can be expensive and require a shutdown of the facility.
Good engineering practice can help prevent issues that may be caused by activities performed in inappropriately controlled environments. The following steps can help manage the process:
Plan your operations throughout your facility, taking into account the requirements for the temperature and humidity in each area and know what activities are most sensitive to the environment. Plans can change, so plan for contingencies whenever possible.
Write down your requirements in a User Requirement Specification (URS) to a level of detail that is sufficient for you to test against once the system is built. This should include specific temperature and RH ranges. You may have additional requirements. Don’t forget to include requirements for instrumentation that will allow you to monitor the temperature and RH of critical areas. This instrumentation should be calibrated.
Solicit and select proposals for work based on the URS that you have generated. The contractor will understand the weather in the area and can ensure that the system can meet your requirements. A good contractor can also further assist with other topics that are not within the scope of this article (particulates, differential pressures, managing heating or humidity generating equipment effects, etc).
Once work is completed, verify correct operation using the calibrated instrumentation provided, and make sure you add periodic calibration of critical equipment, as well as maintenance of your mechanical system(s), to your calibration and maintenance schedules, to keep everything running smoothly.
The main point is if you plan your facility and know your requirements, then you can avoid significant problems down the road as your company grows and activity in various areas increases. Chances are that a typical facility may not meet your particular requirements, and finding that out after you are operational can take away from your vacation time and peace of mind. Consider the environment, its good business!
We have two key software platforms at our laboratory that help us stay compliant with our standard operating procedures. Saif Al-Dujaili, quality manager at Eurofins-Experchem, oversees quality assurance in our laboratory. As we like to say, you are safe with Saif.
A Customized Sample Tracking System
Sample-tracking software consists of four main modules:
Tracking samples in our facility: When a sample is booked by our tracking system, a unique identification number is generated by the system and printed on a sticker, which is placed on the sample. When a sample is booked, department heads then have the ability to assign work orders to the analysts through the tracking system.
When testing is complete, results are entered by the analyst into the tracking system and reviewed by the quality assurance (QA) department. QA reviewers are responsible for approving results entered in the system before they are sent to the client. A certificate of analysis is then generated and e-mailed to the client for their review.
Controlling stability studies conducted in our facility: Stability studies are scheduled and controlled on different samples pulled for analysis. Within our facility’s sample-tracking system we have different chamber names with different conditions where products can be placed. Which chamber we place samples in depends on protocols and requests from our client. The software used also generates a unique study number for each stability study that occurs. The stability schedule that includes each study is reviewed every week by the stability coordinator to schedule what samples need to be pulled for testing.
Controlling methods used for tests: Methods are entered into the tracking system after department heads have reviewed them and it is approved by QA. The tracking system generates a unique ID number for each method as well as each sample. The method can now be tracked in our laboratory’s system. Within the software you can enter the name of the method, client name and effective date and any revisions applied to the method.
Controlling inventory of columns and electrodes: Sample tracking also helps us with our purchasing patterns to make sure we have supplies for our client’s testing needs. Every time that columns and electrodes are received, they are entered into our tracking system for inventory purposes.
REES Environmental Monitoring Software
REES is used to monitor the environmental conditions of our testing facility. Key inputs measured include temperature, humidity, differential pressure and elimination or intensity of light. REES is linked to the QA department’s computers. An audible alarm is sounded as well as e-mails sent to QA personnel to notify them if anything is out of specification. REES also phones related personnel’s cell phones to notify them of any alarms. No alarms are missed, even if they occur after working hours. Having a 24-hour environmental monitoring system in place helps Eurofins-Experchem ensure integrity in operations of stability, microbiological and other environmental conditions essential for accuracy in testing results.
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