Title: Ch. 7.2.3
Course: Lab Safety > Section: Day 5

Adapted from Laboratory Safety by Hill and Finster, 2010 Johy Wiley and Sons

Q: What is the reasonable "turnover rate" for air in a chemistry laboratory?
- One room volume per hour
- Three room volumes per hour
- Six room volumes per hour
- Six room volumes per 8-hour day
A: Six room volumes per hour

Q: In a laboratory, it is safe to assume that, with a proper turnover rate for room air
- All of the air in the lab gets exchanged frequently enough
- Some of the air will be exchanging frequently enough, but not all areas of the lab undergo adequate air mixing
- All of the air in the lab gets exchanged frequently enough as long as there are no windows to open
- All of the air will get exchanged enough as long as the hoods are working at full capacity
A: Some of the air will be exchanging frequently enough, but not all areas of the lab undergo adequate air mixing

Q: A properly "balanced" building, with regard to air pressures, is one where the labs are at a
- Negative pressure compared to hallways outside the lab, thus preventing airflow into the lab
- Negative pressure compared to the hallways outside the lab, thus preventing airflow out of the lab
- Positive pressure compared to hallways outside the lab, thus preventing airflow into the lab
- Positive pressure compared to hallways outside the lab, thus preventing airflow out of the lab
A: Negative pressure compared to the hallways outside the lab, thus preventing airflow out of the lab

Q: Air that is exhausted from a chemical hood
- Is recirculated into the building
- Is recirculated, but only back into the labs
- Is recirculated, but only back into the labs after passing through a chemcial filter
- Is not recirculated back into any part of the building
A: Is not recirculated back into any part of the building

Q: If the "make-up" air that comes into a lab "smells like chemicals" this means that
- The hoods need to be set to a higher flow rate
- Lab windows should be opened to allow more fresh air into the lab
- The intake ducts are located downwind of the hood exhausts
- The exhaust ductwork should be disconnected from the intake ductwork
A: The intake ducts are located downwind of the hood exhausts

Q: An anemometer measures
- The difference in air pressure at two locations
- The velocity of the airflow
- The direction of the airflow
- Nonstatic lab pressure
A: The velocity of the airflow

Q: Verical hood sashes should be closed except when
- Measuring the airflow of the hood
- Access to equipment inside the hood is necessary
- There is some chemical reaction occurring inside the hood
- One expects an explosion
A: Access to equipment inside the hood is necessary

Q: Horizontal sashes are useful in situations where
- A vertical sash would be inconveniently heavy to raise and lower
- It is necessary to keep some part of the shield "open" to maximize airflow
- It is desirable to have access to some equipment while still protecting the face and body
- All of the above
A: It is desirable to have access to some equipment while still protecting the face and body

Q: What two categories of materials require special engineering for chemical hoods?  (Select two)
- Radioactive substances
- Perchloric acid
- Bloodborne pathagens
- Toxic gases
A: Radioactive substances; Perchloric acid

Q: Gloveboxes
- Are used when it is necessary to completely isolate lab air from the air inside the glovebox
- Sometimes have argon or nitrogen atmospheres so that air- and water-sensitive compounds can be handled
- Use gloves that can develop leaks over time and should be checked periodically for integrity
- All of the above
A: All of the above

Q: Overhead "snorkels"
- Are a cheaper by "almost-as-adequate" substitute for a chemical hood
- Are used for "local ventilation" where 100% capture is not essential
- Are commonly used over analytical balances that are used to weigh toxic gases
- All of the above
A: Are used for "local ventilation" where 100% capture is not essential

Q: Biological safety cabinets
- Are a common substitute for chemical hoods
- Cannot be used in chemistry labs accoring to federal regulations
- Filter the air before it is exhausted
- Are always exhausted outside the building
A: Filter the air before it is exhausted