Top 10 Piping Applications that Require a Sanitary Seal

Top 10 Piping Applications That Require A Sanitary Seal Banner

Maintaining a safe, secure, and clean work environment is important for all hygienic processors. However, piping that penetrates through walls, exposing your facility to dust, dirt, and providing a breeding ground for bacteria and pests makes maintaining sanitary standards difficult. Without the proper tools, closing gaps that occur can remain an ongoing and costly problem.

This article is designed for mechanical and electrical contractors, production managers, process designers and engineers, and anyone else who has a stake in ensuring that their processing environment remains clean and safe.

Why is it Important to Seal Penetrations?

In all processing facilities, employee and product safety are the foremost concerns. And a major step in maintaining this safe processing environment is to control the conditions in and around the processing area.

Unsealed gaps in floors, ceilings, and walls become pathways that allow airborne particles, moisture, and pests to travel from one area to another where they can contaminate the product and create health hazards for employees.

Sealing all of the penetrations in a process setting is an important component in producing a safe product and maintaining a healthy work environment.

Importance of Sealing Wall Penetrations

What is the Solution?

Penetration Type Determines Sealing Solution

The demands of each application vary widely, so sealing solutions vary depending on a number of factors. In this article, the following applications will be discussed:

  • Sealing new piping
  • Sealing around existing piping
  • Sealing around wire, cable, tubing or hose
  • Fire, pressure or NEMA rating requirements
  • Openings in walls, ceilings, or floors
  • Openings in thin sheet metal or plastic
  • Seals exposed to cleaning solutions or harsh environments
  • Seals located outdoors where they are exposed to sunlight and temperature extremes
  • Tube-in-tube floor or wall transitions

Let’s dive in.

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Pipetite Standard

1. New Piping Installations

While not always possible, the best time to avoid many potential piping penetration problems in new installations is during the original construction of a project. To achieve the advantages of pre-construction penetration design, coordinate with the contractor to determine the number, location, and size of penetrations.

If penetration sleeves are being installed in concrete walls or floors, for example, they can be placed well before the concrete is poured. Incorporating openings into original construction eliminates the time, expense, and mess associated with cutting holes in existing walls and floors.

To minimize the size of the gap between the barrier and the penetrant, make the openings just large enough to allow for vibration and thermal expansion or contraction of the pipe or tube.

Minimizing the difference between piping diameter and opening diameter saves installation time and money by allowing you to use the smallest possible sealing device to cover the opening.

Escutcheon plates are easy to install onto new piping and provide an inexpensive, non-hygienic temporary cover for penetration gaps. However, the caulk or sealant required to make the actual seal for escutcheon plates will eventually cure to the point that it no longer adheres to the plate or barrier. The plate will then separate from the barrier and expose the gap.

The pliability of the food-grade silicone in flexible boots enables installers to stretch boots over the ends of the pipe or tube easily and slide them into position as the piping is being installed.

Once the piping is secured in place, the boot can slide down the piping until the pre-drilled base seats firmly against the barrier; then it can be anchored permanently in place. The flexibility of the boot allows the piping to move as needed without compromising the seal.

2. Existing Piping Installations

Sealing around existing piping penetrations can be a bit more problematic than sealing around new installations. With existing piping, you no longer have the advantage of being able to install the sealing device by simply sliding it over the end of the piping as it is being installed.

Since existing piping is fixed into position and can’t be removed from the opening, the seal has to encircle the piping and then effectively be re-sealed once the piping is secured into place.

For existing pipes

  • A metal escutcheon plate must be cut into two halves and pieced together around the piping, or
  • A single radial split must be made to allow the plate to bend enough to separate and wrap around the piping

In either case, cutting the plate creates an additional seam that must be sealed with caulk or sealant. Over time, vibration and curing can cause the sealant to separate from the plate and expose the seam, so additional applications of caulk or sealant are required periodically to maintain a secure seal.

Pipetite Rebook

Flexible sealing boots address the challenges of sealing around existing piping. The pliable silicone boot has the requisite split which allows it to be wrapped around the piping, the same as would be required with a metal escutcheon plate. The critical difference is that the two reinforced sides of the split seam are made of silicone elastomer that can be crimped together with a stainless steel staple. The result is a permanent, hygienic compression seal that doesn’t crack or separate over time.

Like flexible sealing boots, modular mechanical seal assemblies can be installed into existing piping penetrations but they should only be used in areas that do not require a hygienic design.

Pipetite Sleeve Boot

3. Tube-in-tube Transitions

Floor and ceiling penetrations often incorporate a section of pipe or sanitary tube in the opening as a sleeve to protect the process piping that runs through it. The sleeve serves as a kick-guard and gives the process piping sufficient room to move and vibrate without restriction.

The gap between the floor sleeve (outer tube) and the process piping (inner tube) must be sealed to prevent unwanted particles, moisture or debris from falling through the gap. A tube-in-tube seal for this application must completely seal the gap and allow the inner tube to move and vibrate as needed.

The rigid design of metal escutcheon plates makes them ineffective as a tube-in-tube sealing device. They are, however, often used to cover the gap between the sleeve and floor decking since they can be welded or bolted into place without creating undue stresses on the process piping.

The majority of commercially available flexible boots for transitioning from one piping size to another are engineered for plumbing applications on

  • Roofs
  • Drains
  • Sewers

Most boots don’t provide the hygienic design that is required in processing environments and are typically made from elastomers that do not have adequate resistance to high heat or cleaning solutions. They are molded in specific size combinations that can’t be altered in the field and are usually secured to the piping with a worm gear hose clamp.

Flexible sleeve boots made from hygienic white silicone provide the heat resistance and compatibility with cleaning solutions that are required in processing plants.

Flexible boots have a heavily reinforced lip seal that conforms to the diameter of the sleeve for easy, secure installation. The tapered cone end of the boot can be trimmed in the field to fit pipe and tube diameters. The silicone elastomer stretches tightly around the sleeve and process piping and has enough flexibility to allow movement while dampening vibration.

4. Fire Rated Applications

Combustible oils, explosive dusts, and flammable liquids and gasses are some of the fire hazards that exist in many food and pharmaceutical facilities. Processing environments that contain potential threats to fire safety may be required to seal penetrations with some level of passive firestop that delays or prevents the fire from passing through penetrations.

The requirements for a proper penetration firestop are addressed in numerous standards and codes:

  • Underwriters’ Laboratories UL 1479
  • ASTM E814
  • NFPA 101 and NFPA 70
  • Life Safety Code
  • National Electrical Code
  • International Building Code

Most current standards require more than filling an opening with a firestop sealant. They require a complete system made up of a fire-rated barrier, the penetrating material, and the firestop sealing agent.

The fire codes for your facility are locally developed and enforced, so contact your local fire marshal or building code inspector to learn about requirements for your facility.


Many products specifically address firestop applications for various types of penetrations. These products range from complete multicomponent sealing systems to intumescent (heat expanding) sealants and pillows to fiberglass or mineral wool packing.

Firestop approaches for food, dairy, beverage, or pharmaceutical penetrations should provide an appropriate level of fire protection and hygienically seal gaps to preserve a sanitary environment.

Stainless steel escutcheon plates are not fire-rated and they don’t provide a hygienic seal around penetrants, so they are not viable for sanitary environments.

While flexible silicone boots don’t carry a fire rating, they properly seal penetrations that have been filled with approved firestop insulating products.

Made of high-grade hygienic silicone, flexible boots are temperature rated up to 500° F and will effectively protect your sanitary environment from non-hygienic fire-rated materials inside penetrations.

Pressure Rated Applications

5. Pressure Rated Applications

The majority of penetrations in processing plants don’t require a special pressure rating. The environments are generally open to atmosphere and only need a clean, reliable seal around the penetration to keep airborne particles, moisture, or pests from moving through them.

If you do have a penetration application that requires a pressure-rated solution, modular mechanical seals carry pressure ratings up to 40 psi or more. This rating typically meets or exceeds the performance requirements for most applications.

To be acceptable in a sanitary environment, the modular mechanical seal assembly has to be contained inside a hygienic seal like a flexible silicone boot so that the processing area is protected from the non-hygienic mechanical seal. The watertight silicone boot also protects the mechanical seal from potentially harmful cleaning solutions.

6. Wire/Cable/Pneumatic Applications

All wire, cable and pneumatic tubing that runs in and out of electrical cabinets, control panels and enclosures must be securely sealed to meet NEMA or IP ratings. Rigid plastic connectors or standard elastomer grommets are commonly used to seal these penetrations.

When applications require more flexibility and sealing area than a rigid connector or standard grommet can provide, a silicone grommet offers a tight, reliable seal that stands up to high temperatures and harsh processing environments.

The lip seal is easy to install and the long sealing area allows significant movement without losing its airtight and watertight seal. They are NEMA rated for Type 4, 4X and 6 enclosures and are available in a variety of sizes for sealing cable or tubing up to 1/2” diameter. In their untrimmed form, they provide an excellent solution for covering unused knockout holes in panels and cabinets.

Pipetite Grommet
Electrical Conduit Applications

7. Electrical Conduit Applications

Electrical conduit penetrations in sizes up to 4” are common in process environments. A number of standard conduit connectors are available in a variety of materials and designs for conduit penetrations through knockout holes in thin sheet metal and plastic.

A flexible silicone grommet for large diameters can also provide an airtight, washable seal with the additional advantage of allowing the conduit to move or flex without losing its seal.

The lip seal is secure and installs easily into the knockout hole, and the tapered cone end can be trimmed to size on site. With no exposed threads or crevices, silicone grommets are not only a cleaner option in most cases, but they also give conduit penetrations a neatly trimmed appearance.

8. Air Hoses/Air Lines Applications

For many years the standard fix for air hose or rigid air-line penetrations through walls has been to fill the gap with a liquid sealant and hope for the best. But hoses flex and rigid air lines lurch with pressure fluctuations, so the sealant inevitably tears, dislodges, or falls out completely.

Until it fails, sealants do an adequate job of filling voids and offering some vibration and sound-dampening qualities, but sealants alone can’t withstand the movement and vibration.

The addition of a base-mounted flexible silicone boot on both sides of the wall significantly extends the life of the liquid sealant barriers by supporting the hose or airline and allowing movement without losing the seal.

Air Hoses/Lines
Pipetite Flat

9. Jacketed Tanks and Vessels

External piping penetrations in jacketed processing tanks and vessels need a secure, sanitary seal that allows movement and vibration without compromising the seal. But often the piping that emerges from the tank jackets immediately connects to an elbow, tee, instrument or another piece of equipment that severely reduces the space available to seal the penetration.

These applications require a low-profile solution for sealing the penetration in the jacket. Metal escutcheon plates are sufficiently low profile and are used in some cases but have limitations that preclude them from other sanitary penetration applications (non-hygienic, require caulks or sealants, mounting failures, etc.).

A flat, low-profile version of the cone-style flexible silicone boot is available for these tight-fit applications. They can be trimmed in the field for piping over 5” in diameter.

10. Outdoor Applications

Penetrations located outdoors and constantly exposed to the elements are rarely required to be sanitary, but they must still be properly sealed. The concern becomes less about hygienic sealing and more about durability.

Sealing devices for outdoor penetrations must withstand constant exposure to ultraviolet rays and extreme temperature changes. Stainless steel escutcheon plates can withstand the UV and temperature challenges of outdoor use, but the caulk or sealants they require to provide the actual seal are prone to shrinkage and brittleness over time.

Once an outdoor seal is broken, water and airborne particles can enter the penetration. Flexible silicone boots have proven to be a good solution for outdoor penetrations because of their ability to remain pliant and hold their seal indefinitely, even after years of outdoor use.

Flexible boots are constructed of a silicone compound that is UV stable and has a temperature range of -40° to 500° F, which makes the boots less susceptible to degradation.

Next Steps

Maintaining a safe, secure, and clean work environment is important for all hygienic processors. However, piping that penetrates through walls, exposing your facility to dust and dirt, and providing a breeding ground for bacteria and pests, makes maintaining sanitary standards difficult.

That’s where Pipetite® comes in.

Pipetite is a self-sealing product commonly used in clean rooms and food, dairy, beverage, and pharmaceutical facilities to hygienically seal pipe penetrations. Pipetite provides a long-term sanitary seal to keep rooms isolated from the outside environment. The flexible, airtight seal accommodates process pipe movement, and the sleek silicone design absorbs vibrations.

Pipetite is made from FDA certified high-grade silicone and 316 stainless steel. Pipetite is compatible with a wide range of temperatures—from -40° to 500 °F—and is able to withstand harsh conditions without breaking, fracturing, melting, or morphing.

Pipetite utilizes wall anchors and a patented self-sealing lip around the base, instead of caulking, to maintain a watertight seal between the wall surface and the pipe. This durable product was specifically created as a long-term solution to the challenges of clean room environments.

Central States Industrial (CSI) stocks Pipetite in several styles and sizes to fit different applications. For a complete overview, visit

A Guide to Wall Penetration

This technical guide is a general education tool for mechanical and electrical contractors, process designers and engineers, production managers, and anyone else who has a stake in ensuring that their processing environment is clean and safe.

A Guide to Wall Penetration

Read Guide


Central States Industrial Equipment (CSI) is a leader in distribution of hygienic pipe, valves, fittings, pumps, heat exchangers, and MRO supplies for hygienic industrial processors, with four distribution facilities across the U.S. CSI also provides detail design and execution for hygienic process systems in the food, dairy, beverage, pharmaceutical, biotechnology, and personal care industries. Specializing in process piping, system start-ups, and cleaning systems, CSI leverages technology, intellectual property, and industry expertise to deliver solutions to processing problems. More information can be found at