Can do mech package engineering also.
Rotating, static, even pipeline also can.

go dig out the old posts. 

For consultant sides, mechanical engineers are usually split into two sub-disciplines - mechanical and piping. The job scope varies quite a bit for each discipline.

If you're attached to the piping division, well, the name itself is pretty self-explanatory. Your scope will cover piping equipment, for example valves and pressure vessels. You'll be working closely with piping designers to define piping routes, along with the stress analysis team on FIV, AIV studies along with, well, stress analysis. Piping & piping equipment MTOs and datasheets will come from you too.

If you're offered a mechanical engineering position, your job scope will cover rotating equipment and mechanical skids (CI skids, fuel gas skids, cranes, HVAC etc). Material handling will also form part of your responsibilities.

For both sub-trees, as part of vendor data incorporation, you'll prepare technical requisition packages and will be required to review vendor documents and drawings to ensure that they are in line with your design.

Oh and by the way,
Fire - Technical safety (F&G detectors are under the jurisdiction of C&A)
ACMV - The term HVAC is the norm in this industry. Essentially the same thing though.
Sanitary - Piping

How many years of experience do you have? If >5 years, I suggest you stick to your industry, unless you're willing to take up an entry-level job (RM2.5k - RM3.5k). It's not uncommon for those in construction/semicon jumping over to O&G though, and many are willing to take the pay cut.

Unfortunately now's a bad time to make the switch. Retrenchment exercises are being carried out everywhere.