Salt, Salt Fog, Salt Spray and Corrosion in Electronics

Anyone who’s ever dropped their cell phone in a swimming pool knows that it’s unlikely the device will ever be the same. Even if it’s operational after drying out, any sensitive electronics in the device are likely to suffer corrosion over time.

Salt Fog and Salt Spray in Harsh Outdoor Environments

The real danger with electronics and exposure to saltwater is that it doesn’t take a lot of salt residue to wreak havoc in sensitive circuitry. While fully submerging an electronics component in saltwater will most certainly cause shorts and rapid corrosion of any protective sealants, even a small amount of salt residue carried through salt fog or salt spray will likely damage equipment over time.

How Does Saltwater Impact Electronics?

Salt water contains NaCl (sodium chloride) which can leave a corrosive residue on circuitry and cause irreparable damage. When saltwater dries, the salt residue left behind will most often continue to corrode surfaces long after the initial exposure. Salt is also extremely difficult to clean from circuitry, so the only effective strategy against salt corrosion is to aggressively protect sensitive electronics from salt fog exposure using sealed enclosures or effective filtration solutions.

How to Prevent Damage from Salt Fog and Salt Spray

Protecting against salt fog and salt spray corrosion is a significant challenge for manufacturers of outdoor equipment. While there are many methods for waterproofing printed circuit boards and other electronics from salt air, the primary objective for these manufacturers is to keep salt out of their enclosures altogether. Since air must pass through almost all electronic devices for temperature regulation, one of the first lines of defense against salt fog and salt spray is the air filter.

How Universal Air Filter Provides Salt Fog Protection

Lower cost, longer term protection

The silver and copper used in solders and circuitry along with their close proximity on PCB cards make them particularly vulnerable areas of electronics due to the high reactivity with salt residue.  UAF filters provide a cost-effective alternative to conformal coated circuit cards which can be expensive and only provide short term effectiveness without other forms of enclosure protection.

Standards-based qualitative and quantitative testing

UAF High Efficiency outdoor enclosure filters, WR and OSP filters, have been tested in a GR-487 rated enclosure subjected to GR-487 30 Day Salt Fog test per the ASTM B117 test standard.  In addition to passing the GR-487 visual inspection for salt contamination inside the enclosure (downstream of the filter), UAF performed a quantitative analysis using copper and silver coupons to determine the corrosion reduction downstream of the filter.  The coupon analysis downstream of the WR and OSP filters showed an 85% and 98% reduction, respectively, in corrosion from the salt fog exposure in these tests.

Multiple layers of protection extends filter life expectancy

UAF WR and OSP filters use high efficiency media in combination with hydrophobic mesh or membrane layers for protection against water and salt fog ingress.  Open-cell polyurethane pre-filters provide a low resistance layer of filtration for coarse particulate to extend the life expectancy of the primary WR or OSP filters