# Steam Tables Iapws

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- **Type:** Skill
- **Install:** `agentstack add skill-jskherman-engg-skills-steam-tables-iapws`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [jskherman](https://agentstack.voostack.com/s/jskherman)
- **Installs:** 0
- **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills)
- **Latest version:** 0.1.0
- **License:** Apache-2.0
- **Upstream author:** [jskherman](https://github.com/jskherman)
- **Source:** https://github.com/jskherman/engg-skills/tree/main/skills/steam-tables-iapws

## Install

```sh
agentstack add skill-jskherman-engg-skills-steam-tables-iapws
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# IAPWS Steam Tables

## Overview

Water / steam properties via the IAPWS-95 utilities exposed through
`chemicals.iapws`:

- Single-phase state (T, P): density, enthalpy, entropy, internal
  energy, Cp, Cv, speed of sound, Joule-Thomson coefficient.
- Saturation: `Psat(T)` and `Tsat(P)`.

## Prerequisites

1. `uv` available.
2. On first use, the script writes `LICENSE_NOTIFICATION.txt` listing
   the IAPWS terms.

## When to Use

- Sizing a steam turbine, condenser, or reboiler.
- BFW or condensate stream property work at known temperature and pressure.
- Saturation pressure from temperature, or saturation temperature from pressure.

## Don't use for

- Hydrocarbon systems — use `vle-flash-calculations`.
- Water + hydrocarbon two-phase systems — neither IAPWS nor plain cubic
  EOS handles them well in isolation.
- Supercritical CO2 — use a CO2 EOS (Span-Wagner).

## Utility Scripts

- `uv run scripts/steam_props.py --temperature-k 773 --pressure-pa 1e7 --output /tmp/steam.json`
- `uv run scripts/steam_props.py --saturation --temperature-k 423 --output /tmp/sat.json`

## Procedure

1. Identify the state (T and P) or the saturation calculation (T or P).
2. Call the appropriate subcommand.
3. Inspect the returned properties; if any value seems unphysical,
   recheck T and P bounds against the IAPWS validity range.

## Pitfalls

- Confusing IAPWS-95 (scientific, full phase diagram, accurate near
  critical point) with IAPWS-IF97 (industrial, faster, small region
  discontinuities). For simulation use IF97; for high accuracy near
  critical, use IAPWS-95.
- Treating the IAPWS Psat at the saturation curve as exact; the
  formulation is accurate, but the calling code must be careful with
  rounding near saturation.
- Using IAPWS for sea water or brackish water — salt is not in the
  formulation.
- Using cubic EOS for water/steam utility work — IAPWS is the industry
  reference.
- Mixing kJ/kg (common in steam tables) with J/kg (the IAPWS native);
  the script reports both bases.
- Reporting steam quality in a flash with a non-water hydrocarbon trace
  contamination; IAPWS is pure-water only.

## Fallback Strategies

- If `chemicals.iapws` is unavailable, surface to the user that no
  fallback is available; do not attempt to substitute a cubic EOS.

## Verification

- Run the listed script with representative inputs and an `--output` file when a deterministic calculation is available.
- Confirm the JSON result contains `ok: true`, expected units, and no unhandled warnings.
- Check result magnitudes against the stated assumptions, references, and a hand calculation or known operating range before reporting them.

## References

- `references/iapws_notes.md` — region boundaries and validity ranges.
- IAPWS releases: https://iapws.org/
- `chemicals.iapws` docs: https://chemicals.readthedocs.io/chemicals.iapws.html

## Anti-Patterns

- Using IAPWS for any non-water system.
- Quoting steam properties to four decimal places without naming the
  underlying formulation.
- Mixing multiple water-property formulations within the same calculation
  without naming the switch.

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [jskherman](https://github.com/jskherman)
- **Source:** [jskherman/engg-skills](https://github.com/jskherman/engg-skills)
- **License:** Apache-2.0

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-jskherman-engg-skills-steam-tables-iapws
- Seller: https://agentstack.voostack.com/s/jskherman
- Browse the marketplace: https://agentstack.voostack.com/browse

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Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.