2.2.3.3 SAFETY ISSUES
Bags of cement routinely have health and safety warning printed on them because not only is cement highly alkaline, but the setting process is Exothermic. As a result, wet cement is strongly caustic (water PH=13.5) and can easily cause severe skin burns if not promptly washed off with water. Similarly, dry cement powder in contact with mucous membrane scan cause severe eye or respiratory irritation. Some trace elements, such as chromium, from impurities naturally present in the raw materials used to produce cement may cause allergic dermatitis. Reducing agent such as ferrous sulfate (FeSO4) are often added to cement to convert the carcino-genic hexavalent chromate ( Cr04-) in trivalent chromium (Cr3+) a less toxic chemical species. Cement users need also to wear appropriate gloves and protective clothing.
2.2.4 CEILING
A ceiling is an overhead interior surface that covers the upper limits of a room. It is not generally considered a structural element, but a finished surface concealing the underside of the roof structure or the floor of a storey above. Ceilings can be decorated to taste, and there are many fine examples of frescoes and artwork on ceiling especially in religious buildings
The most type of ceiling is the dropped ceiling which is suspended from structural element above. Pipe work or dusts can be run in the gap above the ceiling, and insulation and fireproofing material can be placed here. other types of ceiling includes the cathedral ceiling, the concave or barrel- shape ceiling, the stretched ceiling and the coffered ceiling. Cove work often links the ceiling to the surrounding walls. Ceilings can play a part in reducing fire hazard, and a system is available for rating the fire resistance of dropped ceilings.
TYPES OF CEILING
Ceilings are classified according to their appearance or construction.
. CATHEDRAL CEILING: is any tall ceiling area similar to those in a church.
. A DROPPED CEILING: is one in which the finished surface is constructed any where from a few inches or centimeters to several feet or few meters below the structure above it. This may be done for aesthetic purpose, such as achieving a desirable ceiling height, or practical purpose such as acoustic damping or providing a space for HVAC or piping. An inverse of this would be a raised floor.
• A CONCAVE OR BARREL-SHAPE CEILING: is curved or rounded upward , usually for visual or acoustical value, while a coffered ceiling Is divided into a grid of recessed square or octagonal panels, also called a “lacunar ceilingâ€.
. A COVE CEILING: uses a curved plaster transition between wall and ceiling, it is name for cove molding, a molding with a concave curve.
• A STRETCHED CEILING (OR STRETCH CEILING): uses a number of individual panels using material such as PVC fixed to a perimeter rail.
2.4 RULES AND GUIDELINES
RULE 1: USERS SHOULD PRACTICE RESPONSIBLE AND ETHICAL BEHAVIOUR INSIDE THE LABORATRIES
Lab admins are to be treated with respect and all their instructions are to be followed.
Users must submit their identification Card (ID) to the lab admin Entering the premises. Anyone caught using the computers with no valid ID will not be allowed to enter the computer laboratories for one month.
The computer laboratory is a placed of work, all users are urged to keep the noise level down to the absolute minimum and to refrain from socializing. Talking loudly and unruly behavior are not allowed.
The one-person, one-machine policy is strictly enforced. watchers will be asked to leave. No loitering or roaming around the laboratory will be tolerated. Eating, gum chewing, drinking, or smoking is not allowed in the computer laboratories. Anyone caught doing so will be asked to leave and will not be permitted to use the lab for one week.
