Burning paper

[Jorge Llambias <jorge@PHYAST.PITT.EDU>]

How do we say in Lojban: "Paper burns at 451 degrees Fahrenheit."

These are the relevant gismu:

pelji     x1 is paper from source x2
jelca     x1 burns/[ignites/is flammable/inflammable] at temperature x2
          in atmosphere x3
kelvo     x1 is x2 degree(s) Kelvin [metric] in temperature (default is 1)
          by standard x3

I will use kelvrfarenxaito for Fahrenheit, but other suggestions are welcome.

Paper is {loi pelji}.

My problem is how to fill the x2 of {jelca}. From the definition, it seems that
a dimensioned number should go there, but there doesn't seem to be any way to
get such a sumti in Lojban.

My attempt is:

        loi pelji cu jelca le kelvrfarenxaito be li vomupa

but this would be correct only if {jelca} meant "x1 burns at the temperature of
 x2",
i.e. x2 is something at the relevant temperature, rather than the temperature
itself.

Opinions, comments?

Jorge