The Egyptian Co. for Manufacturing Perlite & Vermiculite

Typical mix designs are suggested in table (7). The mix is considered as a guide to the application, but minor adjustment in proportions may be required depending upon specific brands of materials and spray guns used. Adequate quality control on the job can be assured by enforcing density and strength requirements.

Mix proportions					Physical properties
Cement (kg)	Perlite Liters	Water Liters	AEA liter	Fiber gm	Density kg/m3	Compressive strength Kg/cm2
50	100	33	0.4	600	1300	40-60

The plastering contractor shall furnish all labor, material, equipment and supervision for installing the perlite – gypsum base coat plaster and finish coat in accordance with the recommendations of the perlite Design. Application of perlite – gypsum basecoat plaster and finish coats shall be in accordance with USASI Specification A42.1

Adequate fire protection for modern demands that structural member be protected from direct attack by flame and that the temperature of the load bearing members be maintained below the critical point at which weakening or failure is likely to occur. Repeated tests have demonstrated perlite–gypsum and perlite Portland cement plaster are exceptionally effective in blocking flames and retarding the transmission of heat due to:

The countless air cells in perlite aggregate make it an excellent insulator. perlite plasters offers up to 4-6 times more resistance to heat transmission than ordinary sand plaster.

Perlite-gypsum and perlite-Portland cement weighs about 60 % less than ordinary sanded plaster.

When exposed to fire perlite plaster releases chemically combined water in the form of vapor, which maintains the plaster temperature at about 100oC, until all of the water has been driven off as steam.

Perlite plaster has low linear thermal expansion compared with sand plaster at high temperatures, which greatly reduces the number and size of cracks, which permit heat and flame to penetrate through the plaster barrier.

General: all metal lath surfaces and gypsum lath ceilings attached by resilient clips shall be three coat work, Unit masonry and gypsum lath may be either three coat or two coat work.

Three Coat Work :

1- Scratch coat: First coat shall be not more than 60 liters of perlite to 9.3 kg neat gypsum. On masonry surfaces, except monolithic concrete, the mix shall be not more than insulation of 80 liters perlite to 9.3 kg, of neat gypsum.

2- Brown coat: The second coat shall be not more 80 liters of perlite to 9 kg. of neat gypsum.

3- Two Coat work: On gypsum lath, the mix for double-up work shall be not more than 70 liters of perlite to 9 kg, of neat gypsum, on unit masonry, the mix shall be not more than 80 liters of perlite to 9 kg of neat gypsum.

4- Monolithic concrete: A scratch coat of bond plaster shall be applied to the cured and dry concrete. A brown coat of not more than 80 liters of perlite to 9.3 of neat gypsum shall be trowel led into the scratch coat before it has set.

When a smooth trowel led time putty gypsum finish is used, it shall contain perlite fines in the proportions of 10 to 20 liters per 9.3 kg gauging plaster.

Specifications presented here in-incorporate portions of United states of America Standards Institute, Standard Specification for Gypsum Plastering A42.1 but vary in format and content to conform to the current recommendations of perlite Institute, Inc.

Mix proportions

Physical properties