Which tag suits outdoor use?
One whose adhesive, substrate and sealing are all specified for it, because the weakest of the three sets the life. Sunlight and daily temperature cycling do more damage than rain, and the adhesive is what gives way first in most outdoor failures.
Three things have to hold
The adhesive, the substrate and the seal. Each has its own life outdoors and the shortest one ends the tag.
A sealed tag on an adhesive that fails in six months is a six month tag. A durable adhesive under a substrate that goes brittle in sunlight is the same story from the other end.
Buyers concentrate on the tag body because that is what a product page describes. The failures happen at the other two.
Sunlight and cycling
Ultraviolet exposure degrades plastics and adhesives steadily, and a south facing installation gets far more of it than a sheltered one.
Temperature cycling is the underestimated one. A surface in direct sun runs well above air temperature during the day and drops at night, every day, and each cycle works at the bond between materials that expand differently.
Freeze and thaw adds water to that cycle. Moisture that entered an edge expands as it freezes, which opens the gap it entered by.
None of this is captured by a water rating, which is why an outdoor specification needs more than one.
Water enters at the edges
A face laminate protects the face and stops at the perimeter. Rain running down a vertical surface finds the edge, and capillary action does the rest.
A fully encapsulated tag has no such edge, which is the practical difference between water resistant and sealed.
Installation matters here too. A tag applied over a seam, a rivet or a textured area has a path underneath from day one.
Mounting on a downward facing or vertical surface sheds water. A tag on an upward facing horizontal surface sits in a puddle every time it rains, and that is a choice made at installation rather than at purchase.
Specifying for outdoors
State the exposure honestly: full sun or shade, vertical or horizontal, sheltered or open, and the temperature range the surface actually reaches.
Ask for the adhesive to be specified separately for outdoor use, and check the application temperature, since installation often happens in the cold and that alone causes bonds to fail later.
Prefer full encapsulation to a laminated face wherever the tag will get wet, and prefer a mechanical fixing where one is possible. A screwed or cable tied disc removes the adhesive from the equation entirely.
And expect a finite life. Outdoor tags are consumables on a multi year cycle, so a deployment plan that includes replacement is more realistic than one that assumes permanence.
Frequently asked questions
How long does an outdoor tag last?
It depends on the exposure, the adhesive and the mounting far more than on the chip. Plan for replacement on a multi year cycle rather than assuming permanence.
Does cold weather stop a tag working?
Reading is largely unaffected. Cold matters at application, because an adhesive applied below its minimum temperature never bonds properly.
Is a mechanical fixing better than adhesive?
Where one is possible, yes. It removes the component that fails first, which is why outdoor discs are often made with a screw hole.
Do outdoor tags need to be on metal tags too?
Only if the surface is metal, and many outdoor surfaces are. The two requirements are independent and both have to be specified.