HA!
I have BS5950 Part 1 2000 on my desk and extacts from the 1985 (original) version. I don't have the 1990 version around.
Table 2 is much bigger in the 2000 version but contains basically the same information as the 1985 version - I infer that the 1990 version would look like either the 1985 version or the 2000 version. I can't remember - it is not the part of the code the gets committed to memory. If it WAS different I would know! Extracting and paraphrasing from the 2000 version, the following partial safety factors seem relevant:
Dead Load (alone and with imposed loads) 1.4
Dead Load with imposed and wind 1.2
Then there are factors for cranes...
Dead load resisting uplift 1.0
Imposed load 1.6
Imposed load with wind load 1.2
Wind load 1.4
Wind load with imposed load 1.2
There is then half a page of factors for tanks, earth pressures, temperature effects and various crane forces acting in combination with dead, imposed and wind...None of which probably have any effect on your case(?)
I read the table (both 1985 and 2000) to mean the following load combinations:
1.4DL + 1.6IL
1.0DL + 1.4WL
1.4DL + 1.4WL
1.2DL + 1.2IL + 1.2WL
Imposed load (IL) is live load and/or snow load.
For uplift conditions, convention in UK practice is to use the load factor of 1.0 on dead loads that are deemed to always be there. If there is a component of dead load that is removable this is usually assumed to be removed when its presence could be beneficial. A nebulous written justification often accompanies the establishment of a partial safety factor of 0.9 or thereabouts.
Serviceability calculations are based on partial safety factors of 1.0 for dead, imposed and wind conditions but clause 2.5.1 states: '...In the case of combined imposed load and wind load only 80% of the full specified values need be considered when checking serviceability...'
I assume that the practice is similar in the US?
We are now potentially talking about actual loads on a physical structure. Please remember that any comments by me in this forum are based on my experience of UK practice but carry no warranty as to their validity. You must confirm to your own satisfaction the applicability of my statements to your problem.
Having said all that; Do please post your conclusions, if you are able.
Good Luck