Is there a code requirement for the distance that a incandescent type A-lamp would be required to maintain from combustible surfaces such as wood?

For instance, if a 60watt A-lamp, screwed into a keyless lampholder in a basement of a dwelling, was within an inch of a wooden rafter, this would seem to be a hazard.

410.5 gives me some guidance, but is there any other clear guideline that would specify distances from combustible material for type A-lamps?

shortcircuit

Depends on the bulb used...do you have a thermocouple handy?

If I remember correctly, industry standards set 140 degrees F as the maximum temperature a fixture can cause on a "flamable" surface.

"within an inch of a wooden rafter, this would seem to be a hazard." - Yep....bulb to the side or below, I think it would be too close.

410.5 Luminaires (Fixtures) Near Combustible Material.
Luminaires (fixtures) shall be constructed, installed, or
equipped with shades or guards so that combustible material
is not subjected to temperatures in excess of 90°C
(194°F).