Document ppv9ZDMDwY5yXkX4D9322xRvd

Concrete does not withstand acids, and in some types of work employees consider con crete too hard and too cold Resilient non slip mats with low heat conductivity can be placed over the concrete where workmen must stand in one position for considerable periods of time Cork tile is desirable for its insulation, re siliency, quietness, high nonshp rating, and ability to withstand light traffic for long peri ods It is not suitable for wet locations or where there are heavy loadings, and it is ex pensive Cast iron plates with checkered or other wise roughened surfaces laid in cement or asphalt are suitable for some types of rough wear such as that in warehouses The slip ping hazard at the door sills of elevators may be reduced by installing steel grating filled with concrete Lead is used for floors exposed to acids and as a mat for secure footing near wood-working or other machines involving serious danger to the operator if he slips and falls Lead is heat conductive, spark resistant, and quiet It should not be used for heavy trucking Zinc also is used for its spark-resistant qual ities, but, compared to lead, it is attacked more readily by alkalies Floors in com pounding rooms where fire and explosion haz ards exist are zinc-covered in some plants Asphalt-base, vinyl-base or linoleum-type tile often is used in offices, laboratories, and workrooms where cleanliness and good looks are important The material is easily cleaned, noiseless, and a poor conductor of heat Magnesite is suitable for light traffic or where light oils are used It must be laid on a ngid base and should not be used where there is excessive moisture or hydrostatic pres sure, as in basements A coating of bitu minous paint is necessary to protect metals such as pipe from contact, since magnesite corrodes some metals Checkered steel plate wears well, but it is noisy and highly conductive of heat and electricity It is relatively nonshppery unless wom smooth or wet with oil Metal grille floors and gratings will not col lect dust, dirt, or liquids but, because of noise, are not often used where hand trucking is done regularly This type of floor material is particularly useful m boiler rooms and over openings Parquet is laid on an underfloor and is suit able for offices If the material is sealed properly, little maintenance is necessary Par quet wears well but may be noisy Rubber flooring is resilient It also has high dielectric strength, which is undesirable where static electricity is a problem However, conductive types of rubber flooring are avail able Abrasive rubber flooring can be used to overcome slippenness Since terrazzo flooring has no joints m the surface, its use eliminates some of the diffi culties that may be encountered with other types of flooring It can be made electrically conductive by grounded grilles It is a con ductor of heat Suitable sealers are neces sary to make the floor impervious to most acids The terrazzo mixture is slippery unless it includes abrasive aggregates Plants requiring extreme cleanliness and sanitary conditions, such as dairies, use ce ramic glazed tile It should be laid in Trin idad asphalt or m cement with a low lime content Two or three layers of asphalt roof ing felt may be laid beneath the tile Wood floors of the proper matenal and con struction are suitable for vanous services ex cept for the obvious objection of a fire hazard Plank or board floors of the softer woods are generally unsatisfactory and a source of nu merous injuries from slipping and falling as well as from splinters and truck accidents A good floor for light manufacturing can be made from matched or jointed hardwood floor ing nailed to a subfloor structure or to sleepers in concrete The thickness of the hardwood flooring will depend on the service to which it will be subjected It is laid with the gram parallel to the hne of truck travel Wood blocks meet many of the lequirements for a good floor Properly made, a floor of this type is relatively noiseless and does not become slippery or cause fatigue If the blocks are laid on a smooth, ngid base, the floor is not likely to crack and will withstand heavy service Blocks impregnated with creosote are nec essary for floors in contact with liquids or moisture Expansion joints are required along walls, columns, and similar places If blocks are laid with a high melting point pitch, hot weather does not create problems Oils and 391