How do you fix a tag to a plaque or a protected monument?

Permission comes first

A monument has an owner, and a protected one usually has a second authority with a say. A plaque on a building is on somebody's wall. None of that is a technical question, and all of it is settled before a tag is bought.

The question those bodies ask is not about NFC. It is what the fixing touches, what it leaves behind, and whether the whole thing can be taken off without a trace. A proposal that answers those three in its first paragraph gets read; one that starts with the technology does not.

What consent requires differs by country and by the status of the object, so the useful advice is to ask early, in writing, of whoever holds that status, rather than to look for a rule on this page.

What to fix it to

Whatever was already added. An interpretation panel, a signpost, a railing, a bench, a bollard, a lectern: all of them are modern, replaceable, and usually within reach of the same visitor.

Bronze is a special case, because a bronze plaque is metal and an ordinary tag flat against it reads nothing at all, as the metal page explains. An on metal construction handles it, and standing the tag off on a separate plate handles it better.

Stone, slate, brick and wood are transparent to the field, so the objection there is never electrical. It is the adhesive, which stains porous stone and can pull a face off soft sandstone when someone removes it, and the adhesive page is the one to read before any trial.

Outdoors the weather decides

Sunlight, frost, rain and whatever the maintenance contractor cleans with are the forces that end an outdoor tag, and the outdoor page ranks them. A tag specified for an indoor gallery fails within a season on a wall.

A tag behind the polycarbonate face of an interpretation panel is protected and still readable, since plastic passes the field, and it is also out of reach of a fingernail. The glass page covers what thickness costs in range.

Mark the spot and say what it does. A visitor at a monument is not expecting a tag and will not find an unmarked one, which the signage page measures, and a printed address beside it keeps the sign useful for everyone who will not tap.

Who replaces it in five years

A heritage trail outlives the project that funded it. The address on the tag has to still resolve when the agency that wrote the content has been reorganised twice, which is the argument the asset page makes for owning the domain and the redirect.

Write down where every tag is and what it points at. A dozen tags along a trail become unfindable within a year if nobody recorded the posts they are on, and the documentation page covers what that record holds.

Expect covering and removal. Anyone can stick their own tag over yours in a public place, which the street furniture page treats as the defining risk of public space, and a maintenance round that looks at the tags is the cheapest defence there is.