HIPS vs HIPPS: why operator-specific terminology matters
Two acronyms, one letter's difference, and in practice they often refer to the same physical system. But on any given FSRU project, using one where the other is expected is the kind of small mistake that propagates through HAZOP reports and SIL calculations until someone has to fix it.
The terminology distinction
HIPPS is the more common form in the wider process safety literature. It stands for High Integrity Pressure Protection System — an instrumented protective system that isolates a downstream low-pressure section from an upstream high-pressure source, typically to avoid the need for a full-flow relief to flare.
HIPS drops the second P. High Integrity Protection System, not specifically pressure. Some operators use HIPS as their house term because the system's protective function isn't always pressure-only — it can cover over-temperature, over-level, or composition interlocks that share the same architectural pattern.
Why it matters
If you're writing a deliverable for a project where the client uses HIPS and your document uses HIPPS throughout, you're technically correct in generic process safety terms but inconsistent with the client's documentation standard. That inconsistency shows up in three ways:
- Document traceability. If the P&ID tag reads HIPS-201 but your HAZOP worksheet says HIPPS-201, search functions and cross-reference tables break.
- SIL calculation boundaries. The scope of a HIPS system on a client-specific drawing may include non-pressure protective functions that a generic HIPPS definition would exclude.
- Class society review. When DNV or ABS reviewers compare your document to the functional specification, terminology mismatches trigger additional clarification cycles.
Practical rule
Always check the client's functional specification and P&ID tagging before you start drafting. If the specification uses HIPS, use HIPS throughout your deliverable. If it uses HIPPS, use HIPPS. Consistency with the client's documentation convention matters more than alignment with generic industry usage.
The deeper point
Terminology consistency in safety-critical documentation isn't pedantry. It's a proxy for whether the document author has actually read the client's functional specification or is working from a generic template. Reviewers notice. It shapes their confidence in everything else in the deliverable.
The same logic applies to other small distinctions that recur on FSRU projects: ESD-1 vs ESD-2 boundary definitions, PSV vs PSD sizing basis, 2-out-of-3 vs 2-out-of-2 voting logic assumed in LOPA analyses. Each of these has a defensible generic convention, and each has operator-specific house usage that overrides the generic form.
When in doubt, read the client's functional spec first. Then write.