The University of New Mexico
Department of Mechanical Engineering
Laboratory Safety Instructions
(ME Laboratory Committee)
Department of Mechanical Engineering
Laboratory Safety Instructions
(ME Laboratory Committee)
This safety manual provides general guidelines for establishing and maintaining safe working conditions in the Department of Mechanical Engineering. Please also follow the safety regulations and policies specified by the UNM Safety, Health and Environmental Affairs (SHEA) .
| Table of Contents | |
| 1. | Emergencies and First Aid |
| 2. | Safety Rules |
| 3. | Fire Safety |
| 4. | Electrical Safety |
| 5. | Chemical Safety |
| 6. | Cryogenic Safety |
| 7. | Radiation Hazard |
(a) Check mouth and throat for obstructions.
(b) Rescue breathing must be started at once. Seconds count!
(c) Do not look around or look for help.
(a) Wrap the injured person to avoid shock, and call immediately for medical attention.
(b) Raise the bleeding part higher than the rest of the body.
(c) Keep victim lying down.
(d) Never use a tourniquet.
If the burn is minor, apply ice or cold water.
In case of a clothing fire:
(a) The victim should drop to the floor and roll, not run to a safety shower. A fire blanket, if nearby should be used to smother the flames.
(b) After flames are extinguished, deluge the injured person under a safety shower, removing any clothing contaminated with chemicals.
(c) Keep the water running on the injured for 15 minutes to remove heat and to wash off chemicals.
(d) Place clean, soaking wet, ice-packed cloths on burned areas, and wrap to avoid shock and exposure.
(e) Do not use a carbon dioxide fire extinguisher on a person with burning clothing; this could cause suffocation or frost-bite. Dry chemical extinguishers will create inhalation hazards and contaminate wounds. Pressurized water can aggravate burn injuries.
(a) For chemical burns or splashes, immediately flush with water.
(b) Apply a stream of water while removing any clothing that may have been saturated with the chemical.
(c) If the splash is in the eye, flush it gently for at least ten minutes with clear water. Wash in a direction away from the other eye.
(d) If the splash is on the body, flood it with plenty of running water.
(e) A shower, hose or faucet should be used in an emergency.
(f) For chemicals spilled over a large area, quickly remove contaminated clothing while using the safety shower; treat as directed under large Thermal Burns. Seconds count, therefore, no time should be wasted simply for modesty.
1. An individual is advised to work only under conditions in which appropriate emergency aid is available when needed. Work when others are around to provide help if it is needed.
2. Do not work in a laboratory wearing loose hair, loose clothing or dangling jewelry.
3. Wear shoes to protect your feet.
4. Protect your eyes. In all laboratories where chemicals are used, there is the hazard of splashes or dust particles entering the eyes. Pressurized or vacuum vessels may explode or implode sending shrapnel through the laboratory. While working with electrical wiring there are hazards from molten solder and debris. All of these activities require the use of either safety glasses or face shields.
5. Protect your ears. The healthy ear can detect sounds ranging from 15 to 20,000 Hz. Temporatory exposure to high noise levels will produce a temporatory hearing loss. Long term exposure to high noise levels produces permanent hearing loss. There appears to be no hearing hazard (although possible psychological effects) to noise exposures below 80 dB. Exposure above 130 dB is hazardous and should be avoided. Ear muffs offer the highest noise attenuation, and are preferred for levels above 95 dB. Ear plugs are more comfortable and are applicable in the 80-95 dB range.
6. Use respirators when necessary.
1. All containers must be labeled, including such harmless items as distilled water. The label should contain the proper name of the chemical and, if appropriate, a statement of hazards (with the most severe first), precautions, date of purchases or synthesis, and the nature of the user or laboratory.
2. Do not use chemicals from unlabeled containers. The need for adequate labeling extends beyond the immediate requirements of the individual users, since they may not be present in case of fire or explosion, or when containers are broken or spilled. Also, they may no longer be associated with the laboratory years later when containers have deteriorated or have otherwise lost their value.
3. Do not pipet by mouth.
4. Clean spills promptly, especially mercury, oils, etc.
5. Items that might cause thermal burns should not be left unattended if not labeled with a warning.
1. Use only Pyrex or shatterproof glassware.
2. Never use cracked or chipped glassware.
3. Insert tubing properly into stoppers (i.e., use lubricants, hand protection).
1. Before using an instrument or machine, be sure to know how to turn it off in case of emergency.
2. Check all electrical connections and mounting bolts before each use.
3. Check that all rotating parts are free to turn, and that there is no mechanical obstruction before operating.
4. Attach an emergency shutdown card to any piece of equipment left operating unattended outside normal working hours. This card should contain your phone number and all information that would be required by anyone who might be faced with the need to shut down the equipment.
5. Laboratory equipment is not to be placed in corridors.
1. Secure gas cylinders with a strap or chain, whether or not they are in use.
2. Transport gas cylinders with cap on, on a proper cart.
3. Do not use an open flame near gas cylinders.
4. Do not use grease on gauges or connections.
5. Before using gas in an experiment, be sure there are no leaks in the system.
6. Learn directions for closing and opening valves. (All main valves close clockwise.)
7. Do not use adaptors to connect regulators. Use only regulators specified for the particular gas.
Electricity is in constant use both within and outside the laboratory. With direct current, a person can detect a "tingling" feeling at about 1 mA and the median "let-go" threshold (the current at which one cannot release the conductor) is about 76 mA. For 60 Hz alternating current, the values are about 0.4 mA and 16 mA, respectively. In general women are more sensitive to the effects of electrical current than men. Higher currents produce respiratory inhibition and ultimately cardiac arrest.
Although minute electrical shocks are generally considered annoying rather than harmful, such shocks constitute an ominous warning of the presence of potentially hazardous conditions. The device in question should be disconnected immediately and the cause ascertained by a person competent in such manners. Work on electrical devices should be done only after the power has been shut off in such a manner that it cannot be turned on accidentally. Internal current-carrying devices such as capacitors must be discharged.
It is important that all "home-made" electrical apparatus be inspected and approved by someone competent in electrical circuitry before being placed in service.
The following are a list of rules for working with electrical equipment.
In the event of an electrical fire:
Take great care in setting up chemical reactions that are to be left unattended for any period of time. The possible hazards that might arise from failure of a heating mantle (overheating), failure of a water cooling system (hose becoming disconnected or bursting), and failure of an exhaust (if flammable solvents or poisonous gases are evolved), are obvious points to check before leaving a reaction unattended. Any reaction that is left unattended should be clearly labeled as to the nature of the reaction and its components, the possible hazards (i.e., poisonous vapors), and the name and phone number of the experimenter.
Before beginning a chemical reaction the experimenter should have an idea of how it will proceed. Thus, ice baths can be ready if it is exothermic; a vent should be available if gases are generated; automatic shutdown should be incorporated in event of loss of electrical power, cooling water, etc.
5.2.2 Ethers
Ethyl ether, isopropyl ether, dioxane, tetrahydrofuran and many other ethers tend to absorb and react with oxygen from the air to form unstable peroxides which may detonate with extreme violence when they become concentrated by evaporation or distillation, when combined with other compounds that give a mixture that can be detonated, or when disturbed by unusual heat, shock or friction (sometimes as little as unscrewing the bottle cap). This class of compounds should be avoided if there is a safer alternative. It is generally recommended that ethers which will form peroxides should be stored in full, airtight, amber glass bottles, preferably in the dark, or in metal containers. Although ethyl ether is frequently stored under refrigeration, there is no evidence that refrigerated storage will prevent formation of peroxides. Furthermore, leaks can result in explosive mixtures even in refrigerators, since the flash point of ethyl ether is -45 C (-49 F).
5.2.3 High Energy Oxidizers
The momentum imparted to glass fragments by explosion or detonation of 0.25 g or less of high energy oxidizers can be absorbed by protective clothing consisting of leather gloves, coat, and face shield over safety glasses. Hazards can be minimized by diluting oxidizers, limiting the experiment to small-scale reactions, and remote operation behind safety barriers.
5.2.4 Perchloric Acid and Perchlorates
Cold perchloric acid has the properties of a strong acid. When hot, it is also a strong oxidizing and dehydrating agent. It becomes unstable with time and will detonate under shock. Perchlorate compounds will often explode from heating, in contact with flame, by impact, or friction, or spontaneously. Perchloric acid forms explosive compounds with both organic and inorganic chemicals. Because of these hazards, perchloric acid must be used in a specially ventilated hood equipped with water spray and washdown, in which no other types of chemical reactions have ever been vented, and which is not lubricated with organic lubricants. It is imperative that no one attempts to store or use perchloric acid or perchlorate compounds without the prior knowledge, instruction, and supervision or approval of senior laboratory personnel.
Handle any liquefied with care. At these extremely low temperatures, these gases can produce an effect on the skin similar to a burn. Eyes should be protected with a face shield or safety glasses. Gloves should be worn. Stand clear of the boiling and splashing liquid and its issuing gas. Should any liquefied gas contact the skin or eyes, immediately flood that area of the body with large quantities of unheated water and then apply cold compresses.
Oxygen is removed from the air by liquid nitrogen. Therefore, use liquid nitrogen only in a well ventilated area so that the ambient oxygen concentration does not drop lower than 16% (same for liquid helium).
The high pressure gas hazard is always present when crogenic fluids are used, since these are usually stored at the boiling point. Never obstruct the vent valve on crogenic containers. Wood or asphalt saturated with liquid oxygen has been known to explode when subjected to mechanical shock.
A number of acute and long term effects on humans have been related to exposure from various types of ionizing radiation. Radiation hazards arises when using radio-isotopes, lasers, X-ray generators and plasma torches. Each is hazardous in a unique way. A thorough knowledge of the device or the isotope which is to be used is mandatory. The precautions vary widely. Information pertaining to the particular hazard should be obtained from the faculty or research staff member or technician in charge of the facility prior to use. However, several precautionary procedures should always be followed.