Checklist for Leak Proof Design 2019

Waterproof enclosures are used in all types of industry, from oil fields to consumer electronics.

One problem is that the term “waterproof” is 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 the level of dustproof-ness, while the second indicates how waterproof an enclosure is. See a good table of the IP ratings at https://en.wikipedia.org/wiki/IP_Code

When we do 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 sealing material conforms easily to flange surfaces

  • Variations in temperature and pressure effects

  • Verify elasticity of material

  • Deteriorate over time (i.e. chemicals, cracking, creep)

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

  • RF sealing AND water sealing needed

  • Sufficient clearance for material compression

  • Compression force vs sealing capacity

  • Tolerance allowance / compliance

  • Premade gasket vs dispensed

  • Outgassing concern

  • Availability

  • Cost

  • Manufacturability

Housing material and configuration

  • Type of housing material

  • Environmental resistance (temperature, ice, rain, wind, dust, sun)

  • Shape stiffness vs number of fasteners vs locations for proper compression

  • Mfr compression requirements including tolerance

  • Face seal vs wiping seal vs other

  • Seal designed for water impact deflection

  • Pressure variation management

  • Deterioration over time (creep, cracking, other)

  • Planer vs stepped seal

  • Absolute minimum seal count and length

  • Cost

  • Manufacturability

Type of clamping / compression

  • Sufficient clamping by bolts, screws or other

  • What is the clamping force for proper sealing

  • Flange distortion vs seal tolerance

  • Surface finish of flange required

  • Risk for dirt, water, and other contaminants ingress

  • Drop test impact resistant

  • Circular seal diameter matching mfr requirements.

  • Ease of assembly / disassembly / reassembly

Some of my favorite seal designs for clamshell enclosures