ALLTEX^® & VERMIDUCT^®

Ventilation & Smoke Spill Systems
(Interior Applications)

Introduction

Ventilation systems can be responsible for accelerating the initial spread of fire, for example between rooms within a fire compartment, and perhaps more importantly, by the rapid dispersion of smoke and decomposition products.

Unprotected sheet metal ductwork is able to provide a high degree of resistance to the passage of smoke and decomposition products. However, rapid transfer of heat through the metal, regardless of its thickness, prevents the ductwork achieving any degree of fire resistance without supplementary insulation. When suitably protected with a fire protective coating, the fire resistance level of the air handling system is greatly increased.

Given the complexity and tremendous influence of the ductwork construction on the performance of a fire rated system, Vermiduct^® and Alltex^® were researched and tested as a complete system to include: Large and Small Duct sizes, Access Panels, Ventilating/Inspection Grilles, Variable Hanging Rod sizes, Fan Enclosures, and PVC ductwork (180/180/180 FRL). The system offers a total fire solution to Internal as well as External Fire conditions.

LAF systems allow the designer to confidently give precedence to Building Design requirements rather than those of the metal duct manufacturer. LAF systems were developed in strict accordance with the guidelines set down by major international ductwork Standards such as AS 4254-1995, BS 5588 Part 9 and SMACNA. These are well recognized and widely adopted throughout the Mechanical Industry.

Product Description

The Vermiduct^® and Alltex^® are gypsum-vermiculite and cement-vermiculite blends respectively, with trace chemical additives and lightweight polymer beads formulated for fire protection to air handling ductwork on a variety of backgrounds. They do not contain asbestos nor other forms of fibre. The system complies with the current requirements of many International Building Codes. (2)

Vermiduct^® and Alltex^® were tested in the worst case scenario with the sheet metal ductwork joined with conventional ‘Standing Slide’ joints, considered to have minimal structural properties. The testing of Vermiduct^® and Alltex^® in these extreme conditions allow the Designer the confidence to use these fire protection materials on ductwork manufactured with stronger jointing systems. (2)

Vermiduct^® and Alltex^® materials have proven to be highly cost effective with their low thickness, light weight and inherent noise abatement properties.

Recommended Uses

Application of the Vermiduct^® and Alltex^® may be carried out by mechanical means to interior, exterior as well as PVC ventilation ducts in conjunction with mechanical reinforcement (1). This Data Sheet addresses application to Ventilation systems in general.

Product Characteristics

Tested Properties

Alltex^® Note: (*)300 - 1200 kg/m³ Density of Alltex^® may be Engineered to specific application (i.e. Fire, Acoustic, Thermal etc.)

Application Instructions

Vermiduct^® and Alltex^® are mill-mixed compounds that can be sprayed onto substrates requiring protection at the corresponding thickness stipulated by the Manufacturer (refer Thickness Tables over). The element being protected should be free from: rust, oil, excessive dust or any other substance which may impair proper adhesion of the spray material to the background.

Exhaust Ducts

Mechanical reinforcement in the form of chicken wire (typically 25 mm x 25 mm x 1 mm) is required for interpolated thickness applied to every type of exhaust duct or where a fire is likely to develop internally. Typical installations: Kitchen Exhaust, Smoke Spill, Return Air and Exhaust Air, to name the most common.

Supply Ducts

Cementitious materials have been applied to sheetmetal ductwork for Decorative, Acoustic and as an ‘Anti-drumming’ compound since the 60’s. These applications have withstood the ‘Test of Time’, and LAF embarked on a Testing program whereby Supply Air Ducts were subjected to standard fire tests and mechanical reinforcement was omitted and replaced by a ‘Primer/Bond-coat’ equal to Vermitex® ‘7’. These fire tests confirmed that the spray material is retained for the duration of the test.

Strict quality control measures must be implemented to ensure the sheet metal ductwork materials and the workmanship employed are ‘best trade practice’. Notwithstanding the above, and whenever in doubt, we recommend that on continuous smooth surfaces (whether horizontal or vertical, and especially if subjected to continuous vibrations, thermal or construction movement), that mechanical reinforcement be employed with the mesh located at approximately 2/3 through the spray thickness. If mechanical reinforcement is precluded, refer to LAF for further instructions.

Fan Enclosures

Fan Enclosures should be addressed with meticulous design detail. Most international standards such as AS 1668 etc require the ‘full system’, not just the sheet metal ductwork, to be fire isolated. The fan, as well as the motor should therefore be fire isolated. Vermiduct^® and Alltex^® have been approved by the CSIRO to provide fan enclosures with up to 120/120/120 FRL. Fan enclosures measuring up to and including 5m (l) x 2.4m (w) x 3.5m (h) can be catered for. LAF’s fan enclosure systems have been tested in conjunction with Fire Door Frame 2040 mm x 820 mm, Access Panels, Fire Dampers up to 2400 mm wide, PVC Steel and Copper Pipe penetrations as well as Electrical Cable Trays.

Vermiduct^® and Alltex^® , when applied in well ventilated areas to a thickness of 50 mm, will dry in 3-4 weeks. Please note that Vermiduct^® and Alltex^® are prone to frost damage and temperatures surrounding the areas being sprayed should not be allowed to fall below 4°C for a week, after installation. Once the mechanical reinforcement has been secured the whole thickness can be sprayed as one coating, by experienced applicators. Multiple coatings will achieve a smooth and even textured finish, however a new coating should only be applied over one that has partially set. Where this is not possible the last coating surface should be left with a ‘deep & rough texture’ or purposefully scratched. When ‘Trowelling’ or ‘Ruling’ is unavoidable, the applicator should take care not to ‘overwork’ or ‘polish’ the sprayed material.

Vermiduct^® and Alltex^® may be painted however suitable sealers and paints are required. (2)

Ductwork penetrating/passing through walls

Building elements are subjected to severe forces during a fire. The fire causes thermal as well as structural redistribution of loads with substantial movement ensuing. Ducts passing through fire rated and ordinary walls are particularly vulnerable to these forces and must be restrained in place to ensure the construction tolerances on the duct perimeter are retained, to prevent the passage of fire into other compartments/rooms. (2)

Bond Coat, Primer Compatibility and Corrosion prevention

The Vermitex^® ‘7’ Bond Coat is only required for supply air systems subject to the conditions referred to above, in all other cases mechanical reinforcement is mandatory.

Chemicals that have an impact on cement will also have an impact on Vermiduct^® and Alltex^®. In these circumstances, the spray materials should be top coated with a suitable sealer and paint for protection. (2)

For exterior applications where external corner bead protection is required by the Designer, only stainless steel protective ‘Angle Corner Beads’ should be employed. Please note that Vermiduct^® and Alltex^® , may react with Aluminium and Aluminium alloys and a suitable primer is recommended to protect these surfaces.

When applying Vermiduct^® and Alltex^® , to galvanized sheetmetal without the aid of mechanical reinforcement a ‘Bond Coat’ equal to Vermitex^® ‘7’ should be applied. No specific thickness is required when spraying Vermitex^® ‘7’, however coverage of between 50% and 75% of the area is required. Vermitex^® ‘7’ will enhance the adhesion of the Vermiduct^® and Alltex^® , to the substrate as well as facilitate application of the spray material by reducing its ‘slippage’ on smooth backgrounds.

In certain applications,Vermiduct^® and Alltex^® may be applied directly onto the bare steel without the need for a steel primer (Refer to LAF for further detailed advice). If a concern exists about moisture levels, the substrate should be suitably primed with an approved rust preventative primer and ensure that after application the material is top coated with suitable sealers and waterproofing membranes. Membrane/paints based on two pack epoxy resins, chlorinated rubber, solvent based vinyl or solvent based acrylic are normally satisfactory when applied according to the paint manufacturers instructions. (2)

When primers are required alkali resistant zinc-rich primers are recommended, however the paint manufacturer should be consulted to ensure compatibility with Vermiduct^® and Alltex^® LAF have a comprehensive list of compatible primers and will supply on request.

Maintenance and Inspection Hardware

Our 'holistic' approach delivers a number of exclusive features in our system: Access panels, Expansion/Vibration Control Joints and Inspection/Ventilating Grilles which must be installed in accordance with our specifications. (2)

Access Panels:

Access Panels cater for openings from 1.2m x 1.2m down to the smallest opening possible. The exposed face of the access panel is lined with sheet metal for added protection against wear and tear. The panel is affixed by means of self-tapping screws through to a metal C-section which surrounds the duct inspection hatch. Normally the C-section frame is fixed to the sheet metal before spraying, and includes a 2.5 mm perimeter tolerance as well as providing a hard edge to which the spray material is terminated.

Expansion/Vibration Control Joints:

Expansion and/or Vibration control joints have also been successfully tested and may be used in conjunction with Vermiduct^® and Alltex^® systems. (2)

Inspection Grilles:

Services such as Fire Damper Actuators, Sprinkler Penetrations, Smoke Detectors, Thermostats, Registers, Moving Components etc. requiring periodical maintenance and/or servicing are best enclosed in metal boxes, which are later sprayed, and terminating one side with a proprietary Intumescing Grill. The Intumescent Grill allows uninterrupted viewing of equipment within the box, a feature which can save considerable time whilst plant ‘commissioning’ is being carried out.

Coverage

One 50 litre bag of Vermiduct^® or Alltex^® will cover approximately 1m² at a nominal thickness of 50 mm (without wastage considerations).

Vermiduct^® and the Alltex^® Specification (Broad Form)

Prior to commencement of Vermiduct^® or Alltex^® application, the substrate shall be inspected by the Main Contractor to ensure that:

• Air handling ductwork and the work environment are ready for work to commence. Surfaces to be sprayed are free from substances which impair adhesion of the spray material.
  
• All other attachments such as Trapeze/Hanging rods, clips, sleeves, angles, concrete anchors etc. installed by others as required prior to the application of the fire proofing materials are secure.
  
• All ducts penetrating walls/slabs have been secured to wall/slab as approved by the manufacturer.
  
• Non fire-rated ducts, piping, conduits, equipment etc that interfere with the uniform application of the fireproofing material have not been positioned.
  
• Adjacent areas not requiring treatment are suitably protected against droppings and overspray.
  

All structural features, such as duct spans, reinforcement, suspension systems, duct joints etc are to be specified by the Mechanical Consultant and are to be verified by the mechanical contractor to ensure that the system complies with the manufacturer's tested method.

The fireproofing system shall be a surface-adhered, spray-applied material, to be proposed by the system manufacturer, complying with the fire resistance ratings as required by the relevant International Standards and Regulations governing such applications and equal in all respects to Vermiduct^® or Alltex^®.

Vermiduct^® or Alltex^® as manufactured by L & A Fazzini Manufacturing Pty Ltd shall be installed by approved Specialist Contractor to the thickness of ..xx.. mm to provide a Fire Resistance Level of ..aaa / bbb / ccc ..(insert required thickness and FRL).. .

Where applicable, a veneer protective coat equal in all respects to Vermitex^® ‘7’, as manufactured by L & A Fazzini Manufacturing Pty Ltd, shall be spray-applied over Vermiduct^® in accordance with manufacturer's specification and recommendation to achieve a minimum 5 mm to 10 mm thick protective layer to areas as specified.

The Specialist Contractor shall provide all materials, accessories, spray equipment, tools, inspection services and labour to satisfactorily carry out the works in best trade practice. All workmanship and installation techniques shall comply with the Manufacturers ‘Application Instructions’, relevant Building Code Statutory requirements and applicable ASTM, BS or AS Standards.

Refer to Test Data for more information

Vermiduct^®- Ductwork Construction Standard

Tested to AS 1530.4

Vermiduct^® Thickness Table

Tested to AS 1530.4

assessed as complying with BS 476, Parts 20 to 24

Note: LAF Ductwork Construction Standards must be strictly adhered to. (Refer to LAF for further details)

Health Statement

Vermiduct^® or Alltex^® contain no asbestos and present no known health hazard before, during or after application. Normal precautions relevant to the handling of gypsum and cement products apply: dust mask, eye protection and covering of sensitive skin.

NOTES:
1. Refer to LAF for Mesh requirement details and for other Vermiduct^® and Alltex^® applications
2. Refer to LAF for further detailed information

For more information or MSDS on Vermiduct^® or Alltex^® or any other products,

please see the technical data page, or contact: L & A Fazzini Manufacturing Pty Ltd

Email:sales@lafgroup.com