kapilengtips, you may want to familiarize yourself with Table 5.3 of ASME Section VIII, Division 2. The methods (and factors) that you are quoting are from prior editions (NOT CURRENT) of Division 2. For simplicity sake, these are the checks that need to be performed:
P+Ps+D
P+Ps+D+L+T
P+Ps+D+Ss
0.9P+Ps+D+(W or 0.7E)
0.9P+Ps+D+0.75(L+T)+0.75Ss
0.9P+Ps+D+0.75(W or 0.7E)+0.75L+0.75Ss
Where:
P is the design pressure
Ps is the status head of liquid or bulk materials (eg catalyst)
D is the dead weight
L is the appurtenance live load or effects of fluid momentum
E is the earthquake load
W is the wind load
Ss is the snow load
T is the self-restraining load case (such as thermal)
I have argued that piping "thermal' loads are, as jte explained, "restrained free thermal expansion", and should be classified as D, unless it can be positively demonstrated to be otherwise.
In all of these load combinations, per 5.2.2.4.e), Pm is limited to S, PL is limited to 1.5S, and PL+Pb is also limited to 1.5S. Per 5.5.6.1.a), P+Q is limited to Sps, where Sps is the greater or 3Sm or 2Sy.
Specific to your question, I would include earthquake loads in the Sps (the formerly-mentioned 3Sm) check.
A few other things to note:
1) Make sure that you are in the applicability range of the WRC-107 charts.
2) Be absolutely sure that your maximum stresses are at the cardinal-directions. Otherwise, WRC-107 doesn't check those locations, and you may miss the highest-stressed part in your nozzle.
3) If your nozzle has repads, make sure you understand and agree with the methodology that you are using. WRC-107 itself doesn't specifically mention repads at all.
For everyone else ,please note that the CURRENT edition of Division 2 does NOT permit any reduction (the old k-factor) for earthquake anymore. This is a SIGNIFICANT change! The ASCE code made this change several years ago, and ASME has finally caught up. Don't let yourself (or your corporate software) be caught unaware.