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Checklist for Leak Proof Design 2019

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Waterproof enclosures are used in many industries, from oil fields to consumer electronics.

Unfortunately the term “waterproof” tends to be subjective. For your application how “waterproof” is enough?

The “Ingress Protection (IP)” system is an evaluation of electronics housings that gives real meaning to the term “waterproof". It provides real tests that must be passed for different levels. The system has two unrelated numbers following the IP: The first number indicates how dustproof an enclosure is and the second indicates how waterproof it is. A good table of the IP ratings can be found at https://en.wikipedia.org/wiki/IP_Code.

For a waterproof enclosure design, we check all of the items in this checklist and more. Some of the items in the list are general guidelines and we often need to use engineering judgment on the trade-off between the size, cost, and manufacturability of the enclosure.

Sealing material

  • Check that the sealing material conforms easily to the flange surfaces

  • Review possible variations in the effects of temperature and pressure

  • Verify the elasticity of the material

  • Review the deterioration over time (i.e. chemicals, cracking, creep)

  • Check for the risk for dirt, water, and other contaminants

  • Confirm RF sealing AND water sealing as needed

  • Verify sufficient clearance for material compression

  • Review compression force vs sealing capacity

  • Verify tolerance allowance and compliance

  • Review premade gasket vs dispensed gasket

  • Check for the possibility of outgassing

  • Confirm the availability of components

  • Research the cost

  • Review manufacturability

Housing material and configuration

  • Review type of housing material

  • Verify environmental resistance (temperature, ice, rain, wind, dust, sun)

  • Review shape stiffness vs number of fasteners vs locations for proper compression

  • Confirm Mfr compression requirements including tolerance

  • Review face seal vs wiping seal vs other type of seal

  • Check seal designed for water impact and deflection

  • Review pressure variation management

  • Check deterioration over time (creep, cracking, other)

  • Review planer vs stepped seal

  • Verify absolute minimum seal count and length

  • Research cost

  • Review manufacturability

Type of clamping / compression

  • Verify sufficient clamping by bolts, screws or other

  • Check what is the clamping force for proper sealing

  • Review flange distortion vs seal tolerance

  • Confirm surface finish of flange required

  • Review risk for dirt, water, and other contaminants ingress

  • Drop test impact resistant

  • Verify that the Circular seal diameter matches mfr requirements

  • Ease of assembly / disassembly / reassembly

Some of my favorite seal designs for clamshell enclosures