Nearly half of all energy used to power a laboratory is focused on a single function: keeping the room ventilated. From pharmaceutical buildings to educational facilities, chemical fume hoods are a non-negotiable part of safe lab operations.
But what are the actual threats fume hoods protecting your lab workers from – and how do you ensure they are doing their job?
This article answers those questions once and for all. It provides everything you need to understand the role and maintenance of chemical fume hoods – as well as how to find the right certified firm to test your ventilation system.
What is a Chemical Fume Hood?
A chemical fume hood is a mechanical ventilation device designed to limit exposure to hazardous or toxic airborne substances. It works by drawing air into the hood from the laboratory and exhausting it outside the building, thereby lowering the risk of exposure to harmful vapors or gases.
When Should a Chemical Fume Hood Be Used?
Chemical fume hoods should be used within a laboratory as part of standard safety protocols, especially when the safety data sheets (SDS) for chemicals specify the need for ventilation. They are most required when you are:
- Handling Hazardous Chemicals: Whenever you’re working with volatile substances, toxic fumes, or hazardous chemicals, a fume hood helps contain and exhaust the harmful vapors.
- At Risk of Chemical Exposure: If a procedure may involve the potential for chemical exposure through inhalation, a fume hood provides a protective barrier.
- Running Experiments: During experiments that may produce gas, vapor, or air contaminants, fume hoods help maintain air quality and safeguard researchers.
- Mixing and Transferring Chemicals: When mixing or transferring chemicals, a fume hood helps prevent inhalation and reduces risks.
However, chemical fume hoods are not the only equipment used within laboratories to reduce risks – and it’s vital to understand the alternatives.
Chemical Fume Hood vs. Biosafety Cabinet: What’s the Difference?
A chemical fume hood and a biosafety cabinet are both designed to protect users from exposure to hazardous substances, but they serve different purposes and work in distinct ways:
- Chemical fume hoods are primarily used to protect users from hazardous chemical fumes and vapors. While they protect users and the environment, the product itself is not protected.
- Biosafety cabinets use HEPA-filtered airflow to provide a sterile environment for the samples and some types recirculate a portion of the air back into the lab after filtering while other types (B2) exhaust 100% of the air out of the building. This protects users, the environment, and the product – making them perfect for microbiological work, handling pathogens, and other situations where contamination of the product must be prevented.
Biosafety cabinets are therefore necessary for specific instances, but may not be routinely used, and chemical fume hoods may be more common. To understand why fume hoods are still vital in many situations, let’s consider what happens when they are operated incorrectly.
The Safety Risks Chemical Fume Hoods Prevent
Imagine working in a chemical lab with improperly functioning fume hoods or exhaust system: chemical reactions or processes release hazardous gases, vapors, or fumes, but the fume hood system is not protecting you.
This can lead to:
- Exposure to toxic fumes: Toxic vapors, such as volatile organic compounds (VOCs) or carcinogenic substances, can accumulate undetected in the air. In the short term, this may lead to symptoms like dizziness, headaches, and nausea. But over time, chronic exposure to even trace amounts of these chemicals increases the risk of serious conditions, including organ damage and cancer.
- Explosion risk: Laboratories handling flammable or reactive chemicals rely on fume hoods to reduce the danger of accidental ignition. If flammable vapors are allowed to accumulate, it creates a combustible atmosphere that is vulnerable to sparks or heat sources. Additionally, mixing incompatible substances in a poorly ventilated environment can lead to violent chemical reactions.
But the risk to human health is not the only threat poorly functioning fume hoods present; they are also a compliance risk.
What Regulations Are Relevant to Operators?
Several regulations and standards govern the safe operation of chemical fume hoods, ensuring that they operate effectively to protect lab personnel. Key regulations include:
- OSHA Standards: The Occupational Safety and Health Administration (OSHA) provides guidance for laboratory safety, including the proper use of fume hoods to protect workers from harmful chemical exposure.
- ANSI/ASHRAE 110: This is the American National Standard for testing fume hood performance, setting requirements for several procedures, including tests to visualize the flow of fumes, detect low concentrations of tracer gas, and determine if a gas can escape from the hood sash.
What Does Chemical Fume Hood Testing Involve?
Chemical fume hood testing typically involves the three key performance tests:
- Airflow Velocity Tests: These tests are performed to validate the intake airflow velocity meets the specified requirements. Additional tests are performed on variable airflow volume fume hoods to validate the correct operation of the air valve and exhaust system.
- Airflow Visualization Tests: These tests are performed to visually verify the airflow characteristics within the fume hood as well as external room conditions that could affect the fume hood performance.
- Tracer Gas Containment Tests: These tests are performed to verify the fume hood’s containment performance in both static mode and during sash movement.
In concert, these performance tests assess the fume hood and exhaust system to ensure it is properly set up, operates optimally, meets safety standards, and acceptance criteria.
How to Find a Skilled Fume Hood Testing Firm
Finding a skilled fume hood testing firm is crucial to ensure that the tests are conducted accurately and meet industry standards. When looking for a qualified testing professional, consider:
- Experience: Choose a NEBB Certified Firm with experience in performing fume hood tests in your specific industry or laboratory setting.
- References: Ask for references from other laboratory managers or institutions to verify the professional’s expertise.
- Reputation: Research online reviews and testimonials to verify the reputation of the testing professional or company.
NEBB is the international gold-standard certifying agency for over 50 years so you can be confident the professional has extensive technical knowledge, skills, and instrumentation for the discipline.
The NEBB certification process has extensive training, practical exercises, and a written as well as a practical exam. The NEBB FHT Certified Professionals are required to undertake regular supplementary education to stay on top of changing trends and innovations in fume hoods and exhaust systems.
Want to find NEBB-certified fume hood testing firms?