... or more

[Ju1ian]

Dear Teacher,

This question has to do with a common phrase that appears in technical (engineering etc.) texts.

a. iron content of 1 mg/l or more
b. total weight of 30 g or more
c. combined volume of 100 L or more
d. partial pressure of 3 kPa or more
e. comsumption rate of 70% or more
f. diameter of 5 mm or more
g. rotation speed of 1000 rpm or more
h. enzyme concentration of 0.1 mg/ml or more
i. reaction time of 40 min or more
j. vibration frequency of 300 Hz or more
k. average temperature of 120C or more
l. resistance index of 2.5 or more
m. gas price of $3/gallon or more

I feel that some of these are fine but others need to be rephrased to, for example, "or higher", "or larger", "or longer" etc. But I cannot find a clear rule as to when "or more" becomes inappropriate. What I am looking for is a general rule. Please help!

[5jj]

I feel that some of these are fine but others need to be rephrased to, for example, "or higher", "or larger", "or longer" etc. But I cannot find a clear rule as to when "or more" becomes inappropriate. What I am looking for is a general rule. Please help!

A purist might prefer one or other of your expresions in some places, but most of us would be quite happy with 'or more'. Technicians and engineers are more concerned with getting a clear message across than with writing elegant English