For the consumer or "end user" of a "body worn" consumer product, a perfect fit is essential. For users of scuba and respiratory protection masks, a perfect fit can mean the difference between life and death. What is meant by "a perfect fit"? And how can the mask designer ensure this?
First, scuba masks and respiratory protection masks require a perfect seal between the face seal (or skirt) and the face to prevent entry of water or unwanted agents. This is accomplished by the mask designer taking into account the facial characteristics of the end user population and ensuring the mask face seal (or skirt) is sufficiently compliant (flexible) to allow for variations in facial size and feature.
First, scuba masks and respiratory protection masks require a perfect seal between the face seal (or skirt) and the face to prevent entry of water or unwanted agents. This is accomplished by the mask designer taking into account the facial characteristics of the end user population and ensuring the mask face seal (or skirt) is sufficiently compliant (flexible) to allow for variations in facial size and feature.
Second, scuba masks and respiratory masks must be comfortable against the face when they are properly sealed. If excessive and uncomfortable force is needed to achieve a proper seal, users may loosen their mask to achieve comfort, and as a result compromise the integrity of the seal. Mask designers must also design-in a sufficient amount of compliance between the face seal (or skirt) and the face to ensure a wide enough "comfort zone". This refers to a range of mask tightness that is comfortable and easily attainable.
Third, the geometry and cross section of the face seal (or skirt) is critical to achieving proper pressure against the face, and to achieve proper comfort. This includes proper choice of wall thickness and variation of wall thickness where needed.
Forth, the proper material must be chosen for the face seal (or skirt). The mask designer has a range of options that include, but are not limited to: silicone (the most hypo-allergenic to avoid skin reaction), TPE (thermal plastic elastomer) and butyl or nitrile rubber. The durometer or hardness of the material must be taken into account as well, in order to ensure proper compliance, comfort, and durability.
Fifth, the mask designer must ensure that the manufacturing process of the mask is properly monitored. This is to ensure that the design intent and intended behavior of the mask is maintained. Improper molding processes can result in a face seal (or skirt) that does not match the 3D CAD file, and does not meet the durometer expectations.
Sixth and finally, the mask designer must ensure that the mask is properly tested by a representative population of users. This can mean pool and ocean testing for scuba masks, and fit testing for respiratory protection masks.
The scuba and respiratory protection mask designer must take all of these factors into account, to ensure "a perfect fit". And yet, as a customer or "end user" you should not notice any of these efforts. The mask designer's responsibility is to make these factors transparent to you, so that you can enjoy the use of your scuba or respiratory protection mask, whether you're scuba diving in the Bahamas or performing your job in a hazardous environment.
