Only a few years ago, spilling water on your cell phone meant the end of your essential computing device. You could break out the rice or resort to some other tricks, but often, it was unsalvageable. Today, exposure to liquids is not as tragic, but it depends on the specific smartphone. Yet, many may wonder: how exactly are mobile phones “water-resistant” or “waterproof?”
Water resistance in phones is rated to the International Protection (IP) code, which marks the protection of the enclosures on the smartphone to water ingress. IP codes are standardized and kept current through IEC 60529, an international standard developed by the International Electrotechnical Commission (IEC).
What is the IP Code?
IP code ratings go beyond indicating just the water resistance of smartphones. In fact, an IP rating contains two numbers that denote different attributes. As defined in the IEC 60529 Ed. 2.2 b:2013 – Degrees Of Protection Provided By Enclosures (IP Code) standard, the IP Code is:
“a coding system to indicate the degrees of protection provided by an enclosure against access to hazardous parts, ingress of solid foreign objects, ingress of water and to give additional information in connection with such protection.”
With this, there are several main components of to the IP code. The three required elements are the “IP” code letters, the first characteristic numeral, numbered 0 to 6 or the letter X, and the second characteristic numeral, numbered 0 to 9 or the letter X.
IP Code for the Ingress of Solid Foreign Objects (Dust)
The first characteristic numeral indicates the enclosure’s protection against hazardous parts and the ingress of solid foreign objects. With this, the number 0 indicates no protection, and the number 1 demonstrates that the enclosure is protected against “access to hazardous parts with the back of a hand” and “solid foreign objects of 50 mm ∅ and greater.” The degree of protection increases with each successive level, with 6 denoting that enclosures are protected against access to hazardous parts with a wire and are dust-tight.
IP Code for Protection Against the Ingress of Water
The second characteristic numeral demonstrates the enclosure’s protection against the ingress of water through numbers 0-9. This value is determined by testing procedures outlined in the IEC 60529 standard. As with the first characteristic numeral, 0 indicates that the enclosure is not protected, and the degree of protection increases with each increasing number. 1 shows that the enclosure is protected against vertically falling water drops. At the other end of the spectrum, 9 demonstrates that the enclosure is protected against high pressure and temperature water jets.
For example, a the enclosures of smartphone rated IP68 have greater water resistance than one rated IP67.
Optional Elements of the IP Code
The IP coding can also contain two optional characters.
The additional letter A (protected against access with the back of the hand), B (protected against access with a finger), C (protected against access with a tool), or D (protected against access with a wire) can be used if the actual protection of persons against access to hazardous parts is higher than that indicated by the first characteristic numeral.
The other optional feature is the supplementary letter H (high-voltage apparatus), M (tested for the harmful effects of the ingress of water when movable parts of the equipment are in motion), S (same as M but when movable parts are stationary), or W (suitable for use under specified weather conditions with additional protective features).
IEC 60259 Standard for IP Code Degrees of Protection
IEC 60529, the standard for the IP code, does not solely apply to smartphones. It is stated in the scope of the document that it applies to the protection of electrical equipment with a rated voltage not exceeding 72.5 kV. For water and dust protection, the standard considers the enclosures of electrical equipment in this range.
IEC 60529 Ed. 2.2 b:2013 designates IP codes for degrees of protection for electrical equipment enclosures, and, in meeting this goal, it also outlines requirements for each designation, tests to be performed to verify compliance, and relevant definitions.
As an international voluntary consensus standard, ISO 60529 is subject to periodic review to remain current, which is essential considering the ever-rapid evolution of smartphone technology and its utter importance to daily life. In fact, the current edition of the standard, IEC 60529 Ed. 2.2 b:2013 – Degrees Of Protection Provided By Enclosures (IP Code), underwent several changes that updated the IP code ratings. Specifically, this edition saw the addition of second characteristic numeral 9 and the additional letters A, B, C, or D.
Professionals who make use of this standard should be aware that it has two corrigenda documents: IEC 60529 Ed. 2.2 b cor.1:2013 and IEC 60529 Ed. 2.2 b cor.2:2015.
Furthermore, those who need to acquire the IEC 60529 Ed. 2.2 b:2013 standard may consider doing so with the IEC 60529 / IEC 60068-2-1 / IEC 60068-2-14 / IEC 60068-2-31 / IEC 60068-2-78 – Degrees of Protection Package or the IEC 60529 / NEMA 250 – Degrees of Protection Package.
