PERLITE AND
VERMICULITE
PLASTER
SCHUNDLER

MIX DESIGNS
FIRE-RATINGS
CONSTRUCTION GUIDE
The Schundler Company
150 Whitman Avenue
Edison, New Jersey 08817
732-287-2244 www.schundler.com



PERLITE AND VERMICULITE PLASTER

LIGHTWEIGHT and INSULATING FIRE-PROOFING


Perlite and vermiculite plasters consist of a blend of expanded perlite or vermiculite aggregates with either neat gypsum or portland cement. When properly mixed with water they can be applied to walls and/or ceiling surfaces, or to metal wire-lath or gypsum lath for fireproofing structural steel. Both gypsum and cement plasters also can be used for lightweight insulating curtain wall construction and stairwell encasement. Savings in weight, space, labor and building materials are possible.

Gypsum Plaster: Perlite plaster aggregate mixed with gypsum provides an ideal base coat plaster for interior walls and ceilings and for membrane fireproofing to the underside of floor and roof assemblies, or structural steel members.
Sprayed-On Fire-Protection with Schundler Cementitious Fireproofing The Schundler Company has been manufacturing cementitious sprayed-on fire proofing materials for over ten years. In the fall of 2003, it introduced some of its own brands:
Portland Cement: Perlite-portland cement based plaster can be used on new new or on renovation work - as a base coat for stucco finishes, ceramic tile, or masonry veneer. Perlite portland cement plasters are approved for as much as 4-hour fire protection of structural steel columns. They are ideal for weather exposed structural steel elements re-quiring fire protection. Sand aggregate can be added to increase compressive strength. Where desirable all plasters containing portland cement must be applied over metal, or wire lath or other suitable surfaces prepared with an approved liquid bonding agent. Plastering on metal or wire lath is typically three-coat work but some building codes allow two-coat plastering under certain conditions. Two-coat plastering is most typically used in repair and remodeling operations.

Advantages:

  • Lightweight - Weighs approximately 60% less than ordinary sand plaster, saving about one ton (907 kg) for every 100 yd2 (83.6 m2) of material applied in. (13 mm) thick.
  • Insulating - 4 times more resistant to heat transmission than sand plaster... permits savings in heating and air conditioning costs... conserves energy.
  • Fire Retardant - Non-combustible and non-toxic ... provides up to 5-hour fire protection with minimum weight and thickness ... more than 50 fire tested designs by recognized laboratories.
  • Noise Reduction - Reduces sound transmission between partitions. (also see 1 below)
  • Adaptable - Packaged in 3 or 4 cubic feet (85 or 113 liter) bags in the United States and Canada and in 100 liter bags in most other countries. Easy to measure, mix and handle... job mixing permits proper proportioning to meet different plaster based materials specifications.
  • Durable--Cannot rot or decay...strong but not brittle... endures freeze-thaw exposure... successfully used on major construction projects since 1946.

  • Perlite and vermiculite plasters provide protection for columns, partitions, and the undersides of floors and roof assemblies. This protection can be applied with either rough finishes, or in attractive, durable finish.

    During a fire, adequate fire protection demands that the temperature of the load bearing members be maintained below the critical point at which weakening or failure is likely to occur. Repeated test over many years have demonstrated that both perlite-gypsum plaster and vermiculite-gypsum plaster are exceptionally effective in blocking flames and retarding the transmission of heat. When exposed to flames, perlite and vermiculite plasters release chemically combined water in the form of water vapor which helps maintain the plaster temperature to below 212 0F until all of the water has been driven off as steam. Meanwhile, the insulating action of the perlite or vermiculite aggregates delays the release of steam and retards the transmission of heat, thus improving overall fire-proofing characteristics.

    Unlike ordinary sand plaster which can expand and "explode" during fires and/or when subjected to high temperatures, perlite and vermiculite plasters have low linear expansion characteristics which greatly reduce the number and size of cracks. By reducing the number and size of cracks through the plaster, the heat and flames of a fire cannot penetrate the plaster surface as easily or quickly.

Limitations:

  • Normal limitations for gypsum plaster and portland cement plaster apply.
  • Plaster application on any surfaces that have been coated with bituminous compounds is not recommended.
  • Perlite gypsum plaster is not recommended over radiant heating panels because of its insulating value.
  • Long continuous runs of gypsum or portland cement based plaster should be broken to relieve stresses and strain caused by thermal or structural movement.
  • Over monolithic concrete, the thickness of bonding plaster and perlite-gypsum basecoat shall not exceed 3 1/ 8 in. (10 mm) on ceilings and 5 I/ 8 in. (16 mm) on walls. If additional thickness is required to produce desired lines or surfaces, self-furred metal lath shall be secured to concrete surfaces.
  • Gypsum plaster when used with perlite should be milled and set "for use with lightweight aggregates."
  • Where perlite-gypsum plaster with smooth troweled finish is to be applied over expanded metal or wire lath, it is recommended that perlite fines be added to the finish coat mix.

This particular guide specifically focuses on gypsum based plasters. If you want more information about portland cement based plaster, look at our page on cement plasters (Lightweight Fiber Reinforced Perlite Cement Plasters).

PHYSICAL PROPERTIES: The physical properties of perlite and vermiculite plasters vary according to mix designs. They can be designed with a dry density of less than 15 lb/ft3(240 kg/m3) or with the addition of sand or other aggregates up to 45 lb/ft3 (720 kg/m3). Differences in mix designs will affect oven-dry density, insulation (conductivity) and fire-proofing values, and strengths. Some typical mix designs would be as follows:


PHYSICAL PROPERTIES AND MIX PROPORTIONS
FOR VERMICULITE AND PERLITE PLASTERS


TYPICAL PROPERTIES
PERLITE OR
VERMICULITE
AGGREGATE TO
100 LBS. OF GYPSUM
DESCRIPTION
OF USE
OVEN-DRY
DENSITY
PCF
MEAN
TEMPERATURE
CONDUCTIVITY
2 CF/100 LBS Perlite/Vermiculite
-gypsum
scratch coat
44.4 75o 1.42
3 CF/100 LBS Perlite/Vermiculite
-gypsum
brown coat
39.2 75o 1.12


TYPICAL MIX DESGNS FOR
SCRATCH AND BROWN AND FINISH COATS
(in cubic feet of aggregate
per 100 lb. bag of gypsum plaster)
GYPSUM LATH
METAL LATH
MASONRY
TWO COAT WORK
...Double-Up Plastering 2 CF 3 CF n/a
THREE COAT WORK
...Scratch Coat2 CF3 CF2 CF
...Brown Coat 2 CF3 CF2 CF
...Finish Coat1 CF1 CF1 CF
(Please note: these are just some typical mix designs.
Other designs are possible and may be recommended by job conditions,
weather conditions, and different physical requirements.


Ask your perlite or vermiculite supplier for more information about these mix designs,
or contact either:
The Perlite Institute
The Vermiculite Association


APPLICATION: The lightness, lack of compressibility, and low water requirements of perlite-gypsum plasters or vermicuite-gypsum plasters make them adaptable for use with most plastering machines. Both scratch and brown coats may be machine applied on metal lath, gypsum lath, or masonry bases.

SETTING TIME: Plastering specifications usually require that gypsum basecoat plaster have a setting time of not more than four hours. Slow setting plaster may result in a weak basecoat, excessive drying shrinkage and needless finish coat fractures. Neat gypsum and gypsum used in these applications have to be retarded gypsums with a set time of approximately 3-4 hours after mixing.

LIMITATIONS:

  1. Perlite and vermiculite plasters should not be used on exterior surfaces regularly exposed to water or moisture. Where contact with excessive water or moisture is expected, portland cement plaster is recommended.
  2. Plaster applications on any surfaces that have been coated with bituminous compounds is not recommended.
  3. Perlite and vermiculite plasters are not recommended over radiant heating panels because of their insulating values.
  4. Long continuous runs of gypsum or portland cement plaster should be broken appropriately to relieve stresses and strain caused by thermal or structural movement.
  5. Over monolithic concrete, the thickness of bonding plaster and perlite or vermiculite plaster basecoats should not exceed 3/8 inch on ceilings and 5/8 inch on walls. If additional thickness is required to produce desired lines or surface characteristics, metal lath shall be secured to concrete surfaces.
  6. Basecoat plaster shall not abut hollow metal door frames or metal base unless provision is made to lessen vibration by grouting, special anchors, or both. Lath and plaster shall recess into or behind the frame or base.

GUIDE SPECIFICATION FOR PERLITE GYPSUM PLASTER

PART 1.GENERAL

1.01 SCOPE The plastering contractor shall furnish all labor, materials, equipment and supervision for installing the perlite-gypsum base coat plaster and finish coat in ac-cordance with the recommendations as published by Perlite Institute, Inc., applicable drawings, and contract documents. Application of perlite-gypsum base coat plaster and finish coats shall be in accordance with ANSI Specification A42.1.

1.02 WORK BY OTHERS Furring and lathing, sprayed fiber and cementitious mixtures, spray applied decorative finishes, gypsum wallboard or additional material shall be provided by others.

PART 2. PRODUCTS

2.01 IDENTIFICATION AND MARKINGS Identify packaged materials with manufacturers' brand name. Provide similar information in the shipping documents accompanying the shipment of bulk materials.

2.02 DELIVERY AND STORAGE OF MATERIALS Deliver rnaterials to job site in original undamaged containers and store materials off the ground protected from moisture and dampness.

2.03 MATERIALS Materials shall conform to requirements of the referenced specifications and standards and to the re-quirements specified herein:

  • a) Gypsum Neat Plaster- ASTM C-28
  • b) Perlite or Vermiculite Aggregate - ASTM C-35
  • c) Water: clean and potable

Inorganic Aggregates for Use in Gypsum Plaster
(significant specifications of ASTM C-35
Basic Specifications
Density
Sieve Analysis
(Percentage Retained on Each Sieve, Culmulative)
PERLITE
6-12 LB/FT 3
(96 TO 192 kg/m 3)
Sieve SizeMaximumMinimum
No.4 (4.75mm)0...
No.8 (2.36mm)50
No.16 (1.18mm)605
No.30 (600 microns)9545
No.50 (300 microns)9875
No.100 (150 microns)10085
VERMICULITE
6-10 LB/FT 3
(96 TO 160 kg/m 3)
Sieve SizeMaximumMinimum
No.4 (4.75mm)0...
No.8 (2.36mm)100
No.16 (1.18mm)7540
No.30 (600 microns)9540
No.50 (300 microns)9875
No.100 (150 microns)10090

PART 3. - EXECUTION

3.01 PROPORTIONS AND APPLICATION. General: All metal lath surfaces and gypsum lath ceil-ings 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 2 cubic feet (57 liters) of perlite to 100 lbs. (45.3 kg) of neat gypsum. On masonry surfaces, except monolithic concrete, the mix shall be not more than 3 cubic feet (85 liters) of perlite to 100 lbs. (45.3 kg) of neat gypsum.
  2. Brown Coat: The second coat shall be not more than 3 cubic feet (85 liters) of perlite to 100 lbs. (45.3 kg) of neat gypsum.

Two Coat Work

  1. Gypsum Lath - The mix for double-Up work shall be not more than 2 cubic feet (57 liters) of perlite to 100 lbs. (45.3kg) of neat gypsum.
  2. Unit Masonry - The mix shall be not more than 3 cubic feet (85 litters) of perlite to 100 lbs. (45.3 kg) of neat gypsum.
  3. Monolithic Concrete - A leveling coat mix of not more than 3 cubic feet (85 liters) of perlite to 100 lbs. (45.3kg) of neat gypsum shall be applied over an approved liquid bonding agent.
  4. Proportioning of Finishing Coat - When a smooth trowelled lime putty gypsum finish is used, it shall contain perlite fines in the proportions of .5 to 1.0 cubic feet (14 to 28 liters) per 100 lbs. (45.3 kg) of gauging plaster. Specifications presented herein incorporate portions of American National Standards Institute, Standard Specification for Gypsum Plaster-ing A42.1 but vary in format and content to conform to the current recommendations of Perlite Institute, Inc.


TESTING AND APPROVALS

Perlite and vermiculite gypsum plasters have been tested many times by Underwriters Laboratories, Factory Mutual, and many other code authorities. In the past, fire ratings have been given by U.L., N.B.S., Ohio State University, the University of California. Generally gypsum based plasters have achieved far better ratings than cement based plasters, and ratings ranging from 1 to 5 hours have been achieved. See the U.L. Fire Resistance Directory for specific design ratings and information.

SOME TYPICAL U.L. FIRE RATED SYSTEMS
FOR STRUCTURAL COLUMNS
X401 -- 2 HOURS
X402 -- 2, 3 & 4 HOURS
X403 -- 3 AND 4 HOURS
X404 -- 4 HOURS
X405 -- 4 HOURS
X406 -- 4 HOURS
X407 -- 4 HOURS
X408 -- 4 HOURS
X410 -- 3 HOURS
X411 -- 3 HOURS
X413 -- 2 HOURS
N.B.S./BMS-135 --2, 3 & 4 HOURS


SOME TYPICAL U.L. FIRE RATED SYSTEMS
FOR RESTRAINED AND UNRESTRAINED ASSEMBLIES
A406 -- 5 HOURS
A401 -- 4 HOURS
A405 -- 4 HOURS
D403 -- 4 HOURS
D404 -- 3 AND 4 HOURS
D405 -- 4 HOURS
D407 -- 2 HOURS
D910 -- 11/2, 2, AND 3 HOURS
D911 -- 2 HOURS
P405 -- 3 HOURS
P406 -- 3 HOURS
P909 -- 1 HOURS


SOME TYPICAL U.L. FIRE RATED SYSTEMS
FOR WALLS AND PARTITIONS
U-201 -- 4 HOURS
U-203 -- 2 HOURS
U-316 -- 1 HOURS
U-409 -- 1 HOURS
U-413 -- 2 HOURS

Some of these ratings are for perlite, and some for vermiculite.
Please check your U.L. Fire Resistance Directory for the most current values
and for designs, listings of manufacturers, etc.


NEW YORK CITY'S BSA/MEA APPROVALS

In addition, Schundler Perlite Plaster Aggregate maintains in New York City a BSA/MEA approval number of BSA 17-51-SM. Schundler Vermiculite Plaster Aggregate maintains BSA 16-51-SM and BSA 360-51-SM.




1SOUND ADSORPTION OF ACOUSTICAL PLASTERS

The following reverberation absorption coefficients on acoustical vermiculite plaster were measured in a test by the Acoustical Investigation and Research Organisation Limited many years ago. We don't have the original testing information, but felt some information might be better than none.

FREQUENCY BNDS IN REGION (CYCLES)
125
250
500
1,000
2,000
4,000
0.20 0.30 0.50 0.65 0.90 0.90

(The test sample consisted of 12.5 mm (1/2 inch) thick plaster applied by spraying machine to expanded metal lath to which two coats of lightweight plaster had been applied.)



For more information, please call or contact either:

The Perlite Institute
The Vermiculite Association
Or: The Schundler Company

150 Whitman Avenue
Edison, New Jersey 08817
732-287-2244 or www.schundler.com
email: info@schundler.com

Back to Construction Products Main Page

Back to Home Page (Main Page of www.schundler.com)