6.1 Students’ Discipline in the Laboratory
(a) Students should follow strictly the instructions given by the teacher.
(b) Students should not enter the laboratory unless a teacher is present.
(c) Students should not remove anything from the laboratory without permission.
(d) Students should not rush around or play in the laboratory.
(e) Experiments under way should not be left unattended.
(f) Laboratory reagents and chemicals should be returned to the appropriate places immediately after use, with their labels facing the front.
(g) Students should immediately report all accidents and breakages to their teacher.
(h) Students should not suck fingers or pencils when in the laboratory since these may be contaminated with chemicals as well as germs.
6.2 Personal Precautions to be Taken by all Laboratory Users
(a) Eating, drinking and smoking are strictly forbidden in the laboratory and preparation room.
(b) Long hair must be properly tied.
(c) Special care is needed when working with chemicals which have known hazards. It is important to foresee the potential hazards in each case and to take the proper precautions.
(d) Wash hands after experiments, especially those involving the use of chemicals, living organisms and radioactive substances.
(e) To avoid the possibility of allergy, extra care should be taken when handling pollen and fur.
(f) Pipette fillers should be used to help transfer liquid chemicals.
(g) Needle should not be provided for the syringe. The liquid content may squirt into eyes if excessive pressure is exerted on the plunger of the syringe.
(h) Heavy objects should be lifted with correct posture. Ask others for assistance whenever necessary. When carrying heavy objects, especially large bottles containing dangerous substances, appropriate carrier or trolley should be used as far as possible.
(i) Appropriate safety facilities and personal protective equipment should be used whenever necessary.
6.3 Personal Protective Equipment
Students, teachers and laboratory staff, when working in the laboratory, should wear suitable personal protective equipment (PPE) in all circumstances wherever there is any potential risk of bodily injury. All PPE should be kept clean and properly maintained in a serviceable condition. Defective PPE should be replaced immediately.
6.3.1 Safety Spectacles
(a) Each laboratory should be equipped with enough safety spectacles for use by every student. Safety spectacles must be put on when conducting experiment involving heating chemicals, handling acids, alkalis and other corrosive chemicals, working with glass apparatus under pressure, carrying out potentially violent or exothermic reactions, or when there is any potential risk of eye injury. Whenever safety spectacles are required, they should be continually worn by all until everyone has finished the relevant activity.
(b) Scratched or defective safety spectacles should be replaced without delay because they may affect visibility and cause strain to the eyes or fail to serve their protective purpose. Dirty safety spectacles should be cleaned with detergent or disinfectant (e.g. Savlon) as appropriate.
6.3.2 Protective Gloves and Laboratory Gown
Appropriate protective gloves should be worn for hand protection while handling corrosive chemicals, hot objects, microorganisms, etc. Laboratory gown should be worn for body protection whenever necessary. However, torn or ragged clothing can be dangerous instead of protective.
6.4 Using Air-conditioners in Laboratories / Laboratory Preparation Rooms
(a) If schools have installed air-conditioners in their science laboratories / laboratory preparation rooms, all users of these special rooms including students, teachers, and laboratory staff should take appropriate safety measures to ensure that there is adequate ventilation in the rooms during practical activities.
(b) When Bunsen burners or chemicals are to be used, all air-conditioners should be switched off and exhaust fans switched on. The windows of these laboratories should be left open. Notices to this effect should be conspicuously displayed in these laboratories.
(c) To maintain adequate fresh air supply in laboratory preparation room, the exhaust fan must be switched on whenever the room is in use. To this effect, the air-conditioning system and exhaust fan in the preparation rooms must be electrically interlocked so that switching on of the former will automatically turn on the ventilation fan so as to avoid accumulation of gases within the preparation room, but not vice versa.
(d) Chemicals which generate hazardous vapours should not be handled or stored inside preparation rooms, whether or not air-conditioned.
Preparation work which involves unpleasant or hazardous vapours / gases should not be conducted in preparation rooms but in fume cupboards of the laboratories.
6.5 Chemical Spills
Schools should have effective emergency measures to deal with spillage of chemicals. Laboratory staff should be well prepared to handle small-scale spillages that are likely to occur in school laboratories. Methods of safe handling of chemicals and dealing with spillages are usually provided in Material Safety Data Sheets. Adequate safety equipment (e.g. spill control kits and barrier tape, etc.) and personal protective equipment (e.g. protective gloves, respirator and safety
goggles, etc.) should be readily available for use in handling chemical spills. All students and untrained personnel should be kept away from the immediate area of spill.
6.6 Handling Glassware
(a) Large glass bottles should not be lifted or carried by the neck, nor cradled in the arms. The main body of the bottle should be grasped firmly, and trolleys or special carriers should be used.
(b) When a tight glass-stoppered bottle is opened, the bottle should be placed in a trough large enough to hold the contents in case of accidental spillage and the stopper gently tapped. Brief gentle warming of the neck of the bottle can help if appropriate.
(c) The fitting of a pipette filler to a pipette should be done gently. During the process, the pipette should be held at the upper stem to avoid accidental breakage.
(d) When glass tubing and rods are being cut, hands should be protected with a piece of cloth when “snapping” the cut. The sharp ends of glass tubing should always be polished in a flame.
(e) When inserting glass tubing into a cork or rubber bung,
(i) the tubing should not be pointed towards the palm of the hand;
(ii) the size of the hole should be compatible with the size of the tubing and a lubricant should be used; and
(iii) a cork borer can be used to assist the threading of tubing through the hole of a rubber bung.
It is always better to sacrifice a cork by cutting it than to struggle to remove stuck glass tubing.
(f) Glass tubing should be stored vertically, whenever possible. If a horizontal rack is used, the tubing should not protrude beyond the end of the rack.
6.7 Safe Use of Gas 6.7.1 Gas Supply
(a) Schools should never attempt to carry out installation or repair work on fixed gas pipework or appliances. By law, such work must only be undertaken by registered gas installers (RGIs) employed by
contractors registered with the government.
(b) If liquefied petroleum gas (LPG) is used in the laboratory, formal approval must be obtained from the Director of Fire Services and all fire services requirements formulated for such purpose must be observed at all times.
(c) The Gas Authority strongly recommends on safety grounds that LPG cylinders should not be stored inside school science laboratories. For schools in locations where a piped gas supply is not available, LPG cylinders should be housed in an approved chamber external to school premises (i.e. within the entire school boundary but outside the school building) with the gas supply piped into the laboratories. If schools have any enquiries about these recommendations, please contact the Electrical and Mechanical Services Department at 2882 8011.
(d) LPG cylinders must not be used in any locations below ground level where natural ventilation is not possible.
6.7.2 Ventilation
(a) Make sure that ventilation in the room is adequate when Bunsen burners or gas appliances are to be used.
(b) In laboratories and preparation rooms where air-conditioners are installed, all air-conditioners should be switched off and exhaust fans switched on when doing experiments. All windows of these rooms should also be left open.
6.7.3 Gas Burners
(a) The main gas supply valve of the laboratory should only be turned on when gas supply is required, and all downstream gas taps inside the laboratory must be in the OFF position before the main valve is turned on.
(b) Gas taps with safety locks are recommended. Older type of gas taps without safety lock tend to loosen with constant use, and should be checked from time to time and replaced when necessary
(c) The rubber tubings connecting gas taps to Bunsen burners should be of a type suitable for use with the gas being supplied and should
be obtained from the gas supplier. Both ends of the tubings should be held in position by hose clips to prevent loosening. They should be regularly inspected for defects and replaced at least every three years.
(d) All unused gas taps should be properly secured to prevent them from being mistakenly turned on by students. All gas taps should be turned off after experiments have been completed.
6.7.4 Contingency Measures in Case of Gas Leakage
(a) The location of the main gas supply valve to each laboratory (with ON / OFF positions clearly marked) should be made known so that it can be turned off when the laboratory is to be unattended for an extended period of time or in an emergency.
(b) If a gas leak is discovered or suspected,
(i) all gas supply taps including the main valve to the laboratory should be turned off;
(ii) all windows / doors should be opened wide;
(iii) students should be evacuated from the laboratory area;
(iv) electrical switches must not be operated; and (v) all naked flames should be extinguished.
(c) The gas leak should be reported urgently in accordance with the established procedures.
(d) The main gas supply valve must not be turned on again until the gas leak inside the laboratory has been located and repaired by an RGI.
However, when gas continues to escape into the laboratory after the main supply has been turned off, or when a smell of gas persists, then the Fire Services Department and the gas supply company must be contacted immediately in accordance with school emergency procedures.
(e) As LPG is heavier than air, leaked LPG tends to accumulate at low level. It will not dissipate easily unless there is plenty of ventilation at low level. In the case of Towngas, it is lighter than air and can be cleared by opening windows wide.
6.8 Involving Students as the Subjects in Experiments 6.8.1 Handling Spillage of Samples
Any spillage of samples should be cleaned up with disposable absorbent materials immediately. The spill site should then be wiped off with cloth or paper towels soaked in disinfectant (e.g. hypochlorite) and then the cloth or paper towels should be placed in double sealed plastic bags for disposal. In case the skin is in contact with the spillage, wash with liquid soap and water immediately and thoroughly
6.8.2 Disinfection after Practical Work
After practical work, all instruments should be immersed in disinfectant for an appropriate period of time. If they can tolerate heat, they can be boiled for 5 minutes for disinfection, or sterilised by steam under pressure. The bench surface should also be washed with disinfectant. Wash hands thoroughly with liquid soap and water
6.8.3 Smelling and Tasting Substances
In experiments involving smelling of chemicals, students should be reminded of smelling only very small quantities of the chemicals by fanning gently towards the nose. Experiments have to be performed in well-ventilated areas. Tasting should not be carried out in laboratories except for experimental purpose. For experiments involving tasting and smelling items other than chemicals, substances known to be harmless and free from contamination should be used. Substances containing irritants or having allergic effect should not be used.
(Source: Safety in Science Laboratories, updated web version 2008) 7. Outdoor / Fieldwork Activities
Schools should note that outdoor / fieldwork activities must be under the supervision of responsible school staff. Under normal circumstances, a ratio of one staff member to a group of 30 (or below) students is recommended. The school should inform the police and students’ parents / guardians of the route of the trip and the due time of return. Prior written consent from parents / guardians for students taking part in outdoor / fieldwork activities must be obtained. (Please refer to the Guidelines on Outdoor Activities issued
by the Education Bureau.)
8. First Aid in the Technology and Living / Home Economics Special Rooms and