Watertight Expansion Joints and Construction Sealants by EMSEAL

DSF System

NSF-61 compliant joint system for food production and preparation environments

An NSF compliant joint sealant, DSF System features a silicone-bellows sealing surface and a precompressed, impregnated foam backing. DSF provides a lasting solution to joint sealing applications and will not pose a contamination risk to liquids or solids which may be ingested.

The silicone coating is compliant to NSF/ANSI Standard 61 for contact with potable drinking water. It is also in compliance with FDA Regulation CFR 177.2600 for indirect contact with food.

The system is comprised of precompressed, silicone-and-impregnated-foam hybrid installed into field-applied epoxy adhesive on the joint faces with the silicone bellows locked to the joint faces with a silicone sealant band.

For submerged applications subject to hydrostatic-head pressure see Submerseal.

DSF System

NSF-61 compliant joint system for food production and preparation environments


  • Watertight: DSF System is installed with the tensionless silicone bellows facing the liquids, solids, or activities requiring NSF or FDA compliance.  The silicone faced side is watertight.  DSF is also available double-sided so that both sides of a wall can be sealed in a single installation step.
  • Non-Invasive Anchoring: there are no hard metal-to-substrate connections with the DSF SYSTEM. This includes embedded pins, anchors, screws, bolts or tracks, trays or rails. The system is locked to the joint faces by means of the 1) backpressure of the foam; 2) the epoxy adhesive, and 3) the injected silicone sealant band at the joint face to foam-and-silicone bellows interface.
  • Color: The standard DSF SYSTEM color is off-white
  • Versatility: Variations in joint size can be handled through size-switching.
  • Continuity of Seal: as in all EMSEAL expansion joint systems, continuity of seal through changes in plane and direction is an essential performance differentiator. The DSF SYSTEM utilizes EMSEAL’s exclusive “Universal- 90’s”– factory-fabricated single-piece 90-degree units.
  • Double-Sided Straight-Run Option: The DSF SYSTEM is also available with double-sided protection manufactured with the water-resistant bellows on both sides of straight lengths for use in applications where exposure from two sides is possible.


In 1/4″ (6mm) increments from 1/2″ to 8″ (12mm to 200mm) for walls and 1/2″ to 4″ (12mm to 100mm) for floors.

Note: Sizes under 1 1/2″ (40mm) are manufactured with a single bellows. Larger sizes incorporate multiple bellows.


50% Movement (+25/-25%)


Manufactured to resist and not contaminate conditions found
when expansion systems contact water and other clean liquids. Some examples are:

  • Restaurants
  • Cafeterias
  • Food Preparation Areas
  • Food Storage
  • Spill Guards
  • Food Production and Distribution Facilities
  • Proximity to Cleanable, Wipe-able, Nonporous Surfaces
  • The DSF System is produced by coating an impregnated cellular foam with a non-corrosive liquid silicone sealant compliant to NSF/ANSI 61 Standard as well as FDA regulation CFR 177.2600.
  • The external silicone facing is factory applied to the foam at a width greater than the maximum offered extension and is cured before final compression.
  • The silicone application and curing takes place in a factory-controlled environment. In contrast to field-applied liquid sealant and backer rod installations, no movement takes place during curing that can cause deformation or stresses in the material.
  • When compressed, a bellows is created in the coating. As joint movement occurs the bellows simply folds and unfolds free of tension on the bondline, and virtually free of tensile stress in the silicone material.
  • The foam provides a resilient backing to the silicone coating, making the system capable of resisting head pressure and reasonable transient point loads.
  • The DSF System is supplied in 6.56 LF (2m) shrink-wrapped lengths (sticks). “Universal-90” factory-fabricated corners with a standard length of 6-inches (one leg) and 12-inches (other leg) are also available. DSF is precompressed to less than the joint size for easy insertion. After removal from the shrink-wrap and hard board restraining packaging, it expands gradually.

Substrates must be solid, parallel, plumb, free of any contaminants, and capable of resisting approximately 2.5 psi backpressure from the foam.

For continuous immersion or potable water submersion applications — see Submerseal.

Applicable Standards: The silicone coating is compliant to NSF/ANSI Standard 61; NSF Standard 51; FDA Regulation CFR 177.2600; MIL-A-46146; and UL 94 Flame Class, 94 HB.

  • Available for shipment internationally.
  • Prices are available from local distributors or representatives. For more information, contact EMSEAL.
  • The product range is continually being updated, and accordingly EMSEAL® reserves the right to modify or withdraw any product without prior notice.