O

Qwner/user Inspector

Overwater Piping

On-stream Piping

On-site Piping

Off-site Piping

Owner/User

Overdue Inspection Recommendations

Overdue Inspections

OP

OU

Operador

OPD

Owner/Operator

Outsider

Outlet Connection

Outflow

Operated well

Orifice Seal

Open Fire

OWSG

Overlay

Operational Cycle

Operating Temperature Range

Orientation

Offshore Facility

Oxygen-efficient Atmosphere

Operational Risk

Oil-immersion “o”

Oversight & Development

Outside (r) Threat