What is neqsim-psv-orifice-screening?

An educational calculator for estimating the gas-flow opening area needed by a pressure-safety valve and mapping it to a standard valve-orifice letter. A pressure-safety valve opens automatically when pressure becomes too high.

Use it to screen the required valve opening for a gas-relief case and identify a corresponding standard orifice designation.

It provides an early sizing indication before detailed valve selection, vendor checks, and full relief-system design.

neqsim-psv-orifice-screening — Skill by equinor

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent

npx skills add equinor/neqsim-community-skills --skill neqsim-psv-orifice-screening

Clone the repo

git clone --depth 1 https://github.com/equinor/neqsim-community-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/equinor/neqsim-community-skills/neqsim-psv-orifice-screening/github.svg)](https://agentmods.dev/skills/equinor/neqsim-community-skills/neqsim-psv-orifice-screening)

Your own site

<a href="https://agentmods.dev/skills/equinor/neqsim-community-skills/neqsim-psv-orifice-screening"><img src="https://agentmods.dev/badge/skills/equinor/neqsim-community-skills/neqsim-psv-orifice-screening/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/equinor/neqsim-community-skills/neqsim-psv-orifice-screening"><img src="https://agentmods.dev/badge/skills/equinor/neqsim-community-skills/neqsim-psv-orifice-screening.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 64 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,215 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00064	$0.01215
Opus 5.5	$0.00026	$0.00486
Sonnet 5.5	$0.00013	$0.00243
Haiku 4.5	$0.00006	$0.00121

Measured 1mo ago against content hash 1abdbe076eb4, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

neqsim-psv-orifice-screening scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.

The scan reads SKILL.md. This mod also ships 4 executable files (examples/basic_psv_orifice_screening.py, src/psv_orifice_screening/__init__.py, src/psv_orifice_screening/model.py, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/safety/neqsim-psv-orifice-screening/SKILL.md · 110 lines

How it starts

The opening of the file, as written. The whole thing — 110 lines — stays where its author put it; the contents beside it link to each section on GitHub.

PSV Orifice Screening

Use this skill for public, educational pressure-safety-valve (PSV) orifice screening. It estimates the required effective orifice area for critical gas flow using the open API 520 Part I equation and maps it to a standard API letter designation so an agent can scope a relief study before detailed sizing.

When to Use

When a user asks roughly what PSV orifice letter a gas relief case needs.
When an agent needs a quick relief-area triage before detailed API 520 sizing.
When examples must run without confidential valve data, vendor capacity charts, or company relief specs.

Inputs

relief_rate: required relief mass flow W in kg/h.
relieving_pressure: upstream relieving pressure P1 in bar absolute.
temperature: relieving temperature T in kelvin.
compressibility: gas compressibility factor Z, default 1.0.
molecular_weight: gas molecular weight M in g/mol.
specific_heat_ratio: ratio of specific heats k, default 1.3.
discharge_coefficient: effective discharge coefficient Kd, default 0.975.
back_pressure_correction: back-pressure correction Kb, default 1.0.
combination_correction: rupture-disk combination correction Kc, default 1.0.

Outputs

coefficient_c: the C coefficient from k.
required_area_mm2: required effective orifice area.
selected_orifice: the smallest standard API orifice that meets the area, or none.
selected_orifice_area_mm2: the area of the selected orifice.
area_margin_ratio: ratio of selected area to required area.
psv_warning: ok, watch, or oversize-needed.
assumptions: public assumptions used by the placeholder model.

Engineering Method

The Python class PsvOrificeModel uses the open API 520 Part I critical gas-flow equation only:

the coefficient uses C = 0.03948 * sqrt(k (2 / (k + 1))^((k + 1) / (k - 1))) in SI-consistent screening form.
the required area uses A = (W / (C Kd P1 Kb Kc)) * sqrt(T Z / M).
the area is mapped to the standard API 526 orifice letters (D through T) using their published effective areas.
the warning is a simple rule-based label aligned with API 520 intent.

Read the full file on GitHub · 110 lines

Files

What ships with it

6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

1mo ago First seen · 110 lines · 64 tokens per session scan A 1abdbe076eb4

Subscribe to this mod's changes

neqsim-psv-orifice-screening is a skill published in the GitHub repository equinor/neqsim-community-skills (4 stars, last pushed today), licensed Apache-2.0. It adds 64 tokens to every session and 1,215 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-19.

Scientific

neqsim-psv-orifice-screening next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
neqsim-psv-orifice-screeningequinor/neqsim-community-skills	Skill	4	today	Apache-2.0	A	64	Claude Code, Codex
instrument-data-to-allotropeanthropics/knowledge-work-plugins	Skill	35k	3d ago	Apache-2.0	A	123	Claude Code
exploratory-data-analysisK-Dense-AI/scientific-agent-skills	Skill	56k	4d ago	MIT	A	83	Claude Code
matlabK-Dense-AI/scientific-agent-skills	Skill	56k	4d ago	MIT	A	44	Claude Code
phylogeneticsK-Dense-AI/scientific-agent-skills	Skill	56k	4d ago	MIT	A	71	Claude Code, Codex
research-engineerdavila7/claude-code-templates	Skill	33k	yesterday	MIT	A	43	Claude Code, Codex
mapping-to-snomedmaziyarpanahi/openmed	Skill	5.8k	yesterday	Apache-2.0	A	205	Claude Code