>> Oct 14, 2015
Some laboratories perform analysis through the use of analytical chemistry. The scientific method gets its name from the frequent analysis of materials in the liquid phase. Automation has simplified the process of analysis in most settings but the challenge for many labs is in finding a critical environments control solution that is both effective and efficient. One of the most significant areas of concern is the chemical fume hood. This equipment is a significant tool in achieving and maintaining the desired level of control in the airflow system.
The primary objectives of airflow control systems for the laboratory include:
- Operator Safety – Many chemicals and the interactions they produce when combined with various materials result in the release of fumes that are toxic to the operator. An effective airflow system will capture and contain fumes to prevent harm from coming to the operator or anyone within the controlled environment.
- Room Pressurization – Maintains the desired room pressurization of air coming in to that leaving the room to prevent the influx of particulates into or out of the room.
- Ventilation –The volume of air coming into the room should meet the required amount to maintain indoor air quality. The amount of incoming air needs to balance the amount of oxygen and carbon dioxide in the remove while allowing vapors to be given off.
- Comfort – Temperature control provides comfort to operators regardless of the current activities. The type of airflow system will play a role in the ability to maintain a comfortable temperature.
- Reliability – An effective critical environments control solution operates efficiently without the requirement of continual maintenance to address or prevent failures. Phoenix Controls (PhoenixControls.com) has championed the change in chemical fume hood lab control and design to meet the objectives of an effective, reliable critical environments control solution.
The Basics of Fume Hood Control
The simplest method for controlling chemical fume airflow in the laboratory is through the use of constant volume (CV). To achieve this, the fume hood, along with supply and exhaust air flow, are set to a fixed number and maintained. Additional methods can be used for greater efficiency of the system or improved energy efficiency.
The basic idea behind fume hood control is to draw sufficient air through the sash opening while maintaining proper airflow patterns in the cabinet that will prevent hazardous vapors and unpleasant odors from escaping.
Guidelines are provided for controlling the range at which the air travels through the opening in the sash. The “Face Velocity” should be between 60 and 120 fpm while many facilities consider 100 fpm the standard for safe operation. Adjustments may be made without concern for safety when there is no operator in front of the fume hood with any sash position.
The challenge to creating and maintaining critical environments control solutions that really work is designing one that can simultaneously control ventilation and utility connections for accurate and consistent results. While the ventilation hood is a key feature of an effective wet lab environment, there are also other components that must coordinate with the settings for a cohesive solution.
All of the surfaces in a wet chemical lab must be resilient. Not only does this include countertops and equipment surfaces, but the flooring as well. Floors need to be covered with vinyl flooring that is resistant to chemicals. All surfaces need to be seamless and coated with materials that make them impenetrable.
The HVAC is another important component of the wet lab environment. The HVAC system controls temperature and humidity that can impact research. Maintaining a constant temperature is also essential to ensure the equipment performs accurately. Additional filters are included to remove particulates and to improve efficiency. Dust and other particulates can negatively impact experiments and equipment just as temperature and humidity do.
Acid and Corrosives Storage
Keeping acids and corrosives store safely is important to protect the integrity of the surfaces and equipment in the lab and the operator. Vented storage is usually provided under the fume hood along with emergency equipment.
Individual Laboratory Modules
Wet chemistry labs are often divided into separate units with individual connections to the HVAC, gas and utility connections, and safety devices.
Gas and Utility Services
The types of gases and utilities used in the lab depend on the type of experiments performed. A number of utility connections may be used including those for oxygen, carbon-dioxide, or distilled water. The connections for a gas or utility are a part of the building’s distribution system.
Goal of a Critical Environments Control Solution
An effective system will produce optimal results and save the lab money. It needs to be sustainable and should take safety and security into consideration. The emergency equipment stored under the fume hood should be maintained to ensure it works when needed. Hand-held chemical fire extinguishers should be kept available and alarm pulls located throughout. Also, the use of gases calls for toxic gas monitors where gas is stored and used to monitor for potential leaks.
A Good Plan Starts with the Construction
There are a number of relevant codes and standards that apply to the structure and maintenance of a critical environment. The process of meeting compliancy starts with the plan for construction so that the necessary accommodations can be made. The cost of each unit is dependent on the quality of construction and the specific design features. Special features such as revolving darkroom doors for touch-free developing of blots, additional exhaust fume hood systems for large-scale operations, or piping delivery systems to deliver filtered chilled water are examples of details that may be required in some settings and which will provide specific critical environments control solutions that are both practical and efficient.
Some wet chemistry labs are in operation around the clock. In these settings, the equipment and processes are often left on as the cost of shutting down could have a serious impact on the cost-effectiveness of the room. Understanding the needs of the lab related to every area of the processes will help to find better solutions.