Skip to main content

What is the difference? Silicone coated fabrics and silica fabrics for protection of surfaces during hot works

 


 

Introduction

Many high temperature resistant fabrics exist and some are particularly well-suited for welding operations and what is more generally defined as ‘’hot works’’. Such welding fabrics have been thoroughly tested by the U.S. Navy (NAVAL SEA SYSTEMS COMMAND), since welding operations take place at sea. Potential fire would have dire consequences for equipment, personnel and mission operability.

From these testings, specification MIL-C-24576A was established. Three products were specified :

TABLE II

Type I / Class I : Heavy silica cloth (36 oz)

Type I / Class II : Light silica cloth (18 oz)

Type III : E-glass silicone coated fabric : 30-36 oz/sq.yd. / 0.035'' to 0.043'' thick

Comments

For horizontal protection where molten metal will slowly cool down, Robco 188CH (MIL-C-24576A TABLE II - Type I / Class I) remains the material of choice.

For vertical protection, a lighter silica fabric like Robco 84CH (TABLE II - Type I / Class II) is a product with a proven track-record. Most welding fabrics used in the nuclear industry are silica-based fabrics, using as reference MIL-C-24576A.


Recommendations for silicone coated fabrics

6.1.2 Type III material is a glass fabric that has been silicone coated to improve abrasion resistance,

durability, and strength. This silicone coating tends to repel molten metal rather than retain the slag, and is meant to be used in less severe welding and cutting applications than type I. The MIL-C-24576A specification recommends that Type III (silicone coated glass fabric) is for welder’s curtains, and is limited to use in vertical positions. The silicone coating provides the added advantage of repelling liquids, some potentially dangerous.

Silicone coating on welding fabrics typically equates to an amount of approximately 6 oz (total both sides). As per MIL-C-24576A, this means a glass fabric of about 24 to 30 oz. Robco 7320-R fabric falls in that category.

Independent testing at the Alberta Research Council demonstrated that Robco 7171 (red or silver coloured) an 18oz fabric can also perform properly. A report is available upon request.

Can a lighter / more economical fabric be used on vertical applications, even if it means to put multiple layers at a time? From decades of experience, the thinnest/lightest glass fabric ever being used in petrochemical is 17.5 oz (no silicone coating). Thus, depending on the level of activity, the criticality of the area and type of welding operations taking place, the best ratio of safety/cost-performance must be considered.

Conclusion

It all comes down to the best ratio of safety/cost-performance. Robco 84CH silica fabric, silicone coated E-glass fabrics like Robco 7320-R (meeting MIL-C-24576A TABLE II - Type III ) or Robco 7171-R represent good choices of silicone coated E-glass fabrics for the protection of vertical surfaces during hot works. Robco 188CH heavy silica fabric remains the safest material for horizontal protection.

 

Note : Robco products were used as examples as they represent the benchmark for heat resistant fabrics with an excellent track record.

Labels:

Comments

Post a Comment

Popular posts from this blog

Which Removable Insulation Cover Materials to chose?

Flexible, removable insulation covers find application in heavy industries where swift or regular access to equipment is essential. These covers are crucial for insulating heat (or cold) to ensure safety, energy efficiency, and precision in industrial processes. A common inquiry revolves around the choice of fabric under specific circumstances. One pivotal factor to contemplate is whether the material is in direct contact with the equipment or exposed to external elements.   Presented below is a Decision Table to assist you in making informed choices:   Link We hope this table will facilitate your choice next time you require flexible removable cover insulation. Call Robco or Prodimax if you need further information.
Post a Comment
Read more

Choosing the Right Sealing Gaskets for Power Oil Transformers

  Transformers are an essential part of the electrical power distribution grid. Transformer gaskets’ materials are critical for their performance and longevity. Hence, this requires the best selection of sealing materials as leakage can lead to oil contamination of surrounding environment, damaging insulation materials and significantly reducing the life of a transformer. Proper gasket material will help maintain the transformer’s dielectric strength, prevent oxygen, nitrogen and/or moisture leaks, prevent oil contamination and more… Below are some options to consider for proper gasket material selection: Cork with Nitrile binder : traditional material used for decades. Easy to compress in place, fair weather and oil resistance. Low cost Nitrile rubber (NBR) : for general purposes with operating temperature between -30°C to 100°C. Low cost, easily available Fluoroelastomer ( V iton ® B, FKM) rubber : application for higher temperatures to 200°C. Expensi...
Post a Comment
Read more

Quels matériaux choisir pour une couverture isolante amovible ?

  Les couvercles d'isolation souples et amovibles sont utilisés dans les industries lourdes où l'accès rapide ou régulier à l'équipement est essentiel. Ces housses sont essentielles pour isoler la chaleur (ou le froid) afin de garantir la sécurité, l'efficacité énergétique et la précision des processus industriels. Une question fréquente concerne le choix du tissu dans des circonstances spécifiques. Un facteur essentiel à prendre en compte est de savoir si le matériau est en contact direct avec l'équipement ou s'il est exposé aux éléments extérieurs. Vous trouverez ci-dessous un tableau de décision qui vous aidera à faire des choix éclairés :   Lien   Nous espérons que ce tableau facilitera votre choix la prochaine fois que vous aurez besoin d'un isolant souple et amovible. Appelez Robco ou Prodimax si vous avez besoin de plus d'informations.
Post a Comment
Read more