Protective Personal Equipment
Personal protective equipment is a general term used to describe anything you can wear and/or use in order to protect yourself when working with chemical or biological hazards. Common examples of personal protective equipment include: footwear, lab coats, gloves, safety goggles and glasses, face shields, hard hats, respirators, and fume hoods.
Closed toe, leather shoes provide the best general protection. Sandals, sneakers, etc. do not provide adequate protection in case of spills (biological or chemical hazards), or when handling heavy objects, tools, or involved in activities where heavy objects might fall onto the feet. If you will be involved with heavy machinery, steel-reinforced safety shoes may be required. There are also safety shoes specially designed to provide protection against extreme temperatures, caustic chemicals, and/or electrical hazards. . If you will be working in a laboratory presenting any of these hazards for an extended period of time, you should contact your Office of Environmental Health and Safety to see if they will process a request for the purchase of a pair of the appropriate safety shoes.
Lab coats are normally worn in the research laboratory to protect your normal clothing against biological or chemical spills and to provide some additional body protection beyond that provided by your normal clothing. Important considerations in selecting an appropriate lab coat are the types of hazards (biological, chemical, fire, cold, etc.) to which you may be exposed. To be effective, the fabric should be resistant to the materials you are using. In addition, a lab coat should fit properly (you should be able to move comfortably in it with the coat buttoned or snapped down the front), be clean, and have long sleeves. Lab coats are normally provided by one’s laboratory for the duration of the project.
When handling chemical, physical, and/or biological hazards that can enter the body through the skin, it is important to wear the proper protective gloves. Note that there is no perfect glove: There is no kind of glove that will protect you from all hazards. There are several different kinds of gloves: disposable, fabric, leather, and metal mesh.
- Disposable – These are generally used to provide protection against biological or chemical hazards. There are two common kinds of gloves you will find in most biological and/or chemical laboratories – latex and nitrile gloves. Latex gloves provide good general protection in a biological research lab but provide no protection against common chemical hazards. Their use has decreased somewhat in recent years as some individuals have exhibited serious even life-threatening allergic reactions to latex. Nitrile gloves provide good general protection against a wide range of common solvents and chemical reagents. There are many other glove materials available which provide protection against particular chemical hazards. It is important to note that all glove materials are eventually permeated by some chemical reagent. Therefore to be maximally effective, the gloves should be changed whenever they become contaminated by the chemical reagent. The key to glove use is identifying the proper gloves for the job in question. For example, Kevlar gloves will provide good protection from extreme temperatures. Nitrile gloves provide good short term protection when handling a wide range of organic solvents and reagents. Depending on the nature of the hazards peculiar to your research project, you may find that you need several different kinds of gloves in order to be adequately protected. Best Glove Company’s website is a good resource to consult when selecting the appropriate gloves for your work.
- Fabric – Cotton gloves are often used in pilot plants to absorb moisture and provide a better grip when working with heavy machinery.
- Leather – Leather gloves provide good protection when working with flames or when sparks may be present. They are also often worn together with insulated liners when working with electrical hazards.
- Metal Mesh – Metal mesh gloves are preferred when working with heavy machinery and/or cutting tools.
In addition to identifying the correct kind of glove, it is also important to make sure that the gloves that you use fit properly. Most gloves are commercially available in several different sizes. If you will be wearing gloves for an extended period of time (several hours or more), you may find it useful to purchase a box of disposable cotton glove liners that you can wear underneath your disposable gloves. Glove liners absorb perspiration and help minimize skin irritation.
Safety Glasses and Goggles
As a general rule, safety glasses with side shields should be worn at all times in the research laboratory even if you wear prescription glasses. Safety goggles rather than safety glasses are preferred whenever a chemical splash is a potential hazard. The side shields on safety glasses are simply not as effective as goggles in protecting your eyes from small particles and liquid splatter.
Most laboratories provide safety glasses or goggles to their researchers. If you wear prescription glasses and will be working in the lab for an extended period of time, you should contact your Office of Environmental Health and Safety to see if they will process a request for prescription safety glasses (special request). If you wear contact lens underneath safety glasses be sure to consider the additional potential risk that your contact lenses may present if dust, caustic reagents or solvents get underneath your lenses and in your eyes. Removing your contact lenses in such a situation may take added time and increase your risk of injury.
A face shield should be worn whenever there the entire face needs protection. This means any time there is a potential that an aerosol of chemical or biological hazardous material may be created or whenever chemical or biohazards could splatter, or whenever there is the potential for flying particles or sparks (e.g., high pressure work, welding, soldering, machining, fire, explosion, etc.). A face shield should always be worn whenever handling tissue samples or animals where there is the potential for infectious transmission. Safety glasses or goggles should always be worn underneath a face shield for maximal protection.
Hard hats are normally worn when in construction and/or pilot plant work when falling objects or electrical conductors are potential workplace hazards. There are two general types of top hats: Type I and Type II. The former are designed to provide protection for the top of the head while the latter provide protection for the top and off-center protection as well. An excellent introduction to hard hat safety is available on-line at: www.hardhats.4ursafety.com/
Respirators filter contaminants, either small airborne particles or chemicals including gases, out of the air. Whenever possible you should structure your work so that it can be carried out in a hood. Selection and purchase of a suitable respirator should be carried out only in consultation with your Office of Environmental Health and Safety as it is extremely important that the respirator fit properly and that it has the correct filters to be effective when used with your particular hazards. The National Institute for Safety and Health (NIOSH) publishes a useful booklet available on-line at: www.cdc.gov/niosh/docs/2005-100/default.htmldiscussing the selection of respirators. If you are going to work with a respirator, be sure to obtain training prior to using this PPE. One last comment, it is important to remember that to operate properly respirators must be regularly cleaned, sanitized (if biological hazards are involved), and maintained.
Chemical Fume Hoods
Whenever you use flammable or hazardous materials that pose an airborne or explosive hazard, you should work in a fume hood. Exposure is controlled in part through the moveable glass plate, the sash, that covers the front of the hood. Maximal protection is afforded when the sash, if it moves vertically, is closed or lowered as much as possible.
There are different types of fume hoods. Two of the most common types are the constant air volume (CAV) and the variable air volume (VAV) hoods. Constant air volume hoods are designed to maintain a constant air flow that doesn’t vary when the hood sash is opened or closed. The disadvantage of these hoods is that the face velocity increases when the hood sash is lowered or decreases when the hood sash is raised as a result which can lead to either excessive turbulence and the escape of toxic materials from the hood. Variable air volume hoods are designed to maintain a constant face velocity whenever the hood sash is opened or closed minimizing air turbulence at the sash extrema and maximizing user protection.
It is important that there be good airflow to the hood exhaust. Today most hoods are equipped with an airflow meter. These measure the face velocity which is the rate at which air is pulled into the hood exhaust.
Fume hoods should be inspected annually. Dated inspection stickers should be posted conspicuously somewhere on the front of the fume hood. Do not hesitate to contact the Office of Environmental Healthy and Safety at your workplace if you cannot find a sticker or if the sticker is more than one year old.
All hoods are not the same. Depending on the hazards involved in your work, you may need to use a special kind of fume hood.
- Biosafety cabinets should be used when dealing with biological hazards.
- Chemical fume hoods should be used when flammable solvents and/or highly reactive reagents are involved.
- Special fume hoods are required when working with certain radiological hazards such as iodine-125 or when working with perchlorates, which react explosively when mixed with organics.
- Whenever possible endeavor to work with materials that are non-toxic or which present minimal health risks to you and your research group.
- Keep all materials at least 6 inches inside the fume hood. Doing this ensures you maximal protection in terms of hood air flow and air turbulence. A useful visual method of reminding yourself to do this is to place a strip of brightly colored labeling tape 6″ lengthwise inside the hood.
- Never place beakers, pipettes, or other materials on the edge of the hood where they can be easily knocked off and where the hood provides no protective air flow.
- Keep the sash lowered at all times. When you are working in the hood, always keep the sash of the hood below your face.
- Regularly inspect the flow meter in your hood to ensure that the hood is functioning properly. If there isn’t a flow meter contact your Office of Environmental Health and Safety. A simple, effective visual means of determining that there is hood air flow is to tape a kimwipe at the bottom edge of the hood sash. If the hood is operating properly, it should be partially pulled inside by the hood’s airflow.
- Do not put signs, or other materials that impede visual inspection of the hood’s contents on the hood sash. In some organic and inorganic synthesis laboratories, it is common practice to write the chemical reaction on the face of the hood sash. If your lab does this be careful not to obscure your and others’ direct view of the inside of the hood.
- Locate electrical devices such as variacs outside the hood to avoid sparking that could ignite flammable reagents and/or solvents.
- Remember: hoods are not a substitute for good common sense. Do not do anything in a hood that you would not do on a desktop. For example, do not heat flammable solvents in an open beaker directly on a hot plate.
- Fume hoods should not be used to store hazardous materials. The bottles, glassware, and other materials that you place inside the fume hood can interfere with the proper airflow within the hood. Remove reagent bottles promptly when you are finished using them and replace them in their proper storage location in the laboratory.
Best Glove Company has an excellent website that includes an html tool you can use to identify the appropriate glove for your research application. See: “What is the Best Glove for Me?” Avail. URL: http://www.bestglove.com/site/products/whatsthebestgloveforme.aspx
“All About Head Protection.” Avail. URL: http://www.hardhats.4ursafety.com/
“NIOSH Respirator Selection Logic 2004.” Avail. URL: http://www.cdc.gov/niosh/docs/2005-100/default.html
“Chemical Fume Hood Handbook.” (Northwestern University Office of the Vice President for Research) Avail.URL: http://www.louisville.edu/admin/dehs/lsfume.htm