What does it cost, and which iPhone version does it need?

$12.99 USD one time. iPhone, iOS 17.0 or later. Check the App Store for your region's current price and compatibility.

Does it work without signal?

Yes. Every calculator runs on the device. There is no account, no login, and nothing to sync. The only time it reaches the network is if you tap a method citation, which opens the published source in Safari.

Is there a subscription?

No. One price, everything included, no unlock packs and no recurring charge. Updates to the tools you already have are free.

Where do the numbers come from?

Every calculator names the published correlation behind it and links to the source. You can read the method and its validity range inside the app before you trust a result. Nothing is a black box, and no licensed chart or table is reproduced.

What happens if my inputs are outside the method's range?

You still get a result, with the range violation flagged on the card. The app does not refuse to calculate, because an operator working a real problem needs a number and a warning, not an error message.

Can I use this for engineering design?

No. These are field estimates, the same ones done on a whiteboard, computed faster and more consistently. They are not stamped or certified and should never be the sole basis for a safety-critical decision. Verify against your facility's approved methods.

Is there an Android version?

Not currently. PlantHand is iPhone only.

← Ironclad

PlantHand · iPhone

Built by a gas plant operator. Works in the dead zone.

PlantHand is the set of calculators and reference tables a processing plant or pipeline operator actually reaches for on shift. The same estimates you already work out by hand, done faster and more consistently, with the published method named on every result.

Download on the App Store

$12.99 USD one time· no subscription, no unlock packs

Written by a 10 year senior operator on stabilizer and cryo units, who trained and signed off operators before they ran a board. Every calculator names the published method behind it.

The problem

Plant math gets done on a whiteboard, a scrap of paper, or from memory, often away from a reliable connection. PlantHand brings those field estimates together with named methods, validity ranges, and warnings that can be read offline.

A wrong hydrate margin or a mis-sized purge is not a rounding error. It is a line plugged at three in the morning, or a truck that cannot take a full load.

Who it is for

Gas plant and midstream operators, board operators, pipeline techs, and the leads training them. Built for the control room and for the unit, in the dead zone where there is no cell service.

Who it is not for

Drilling and completions. These tools focus on processing plants and midstream operations.

Anyone who needs a stamped or certified number. These are field estimates, the same ones you already work out by hand, and they do not replace engineering design or your facility’s approved methods.

Android users. This is iPhone only, and it is going to stay that way for a while.

Sixteen tools, all offline

Hydrates and injection

Hydrate formation temperature
Methanol injection rate
Glycol (EG) injection rate

Pressure and temperature

JT drop and letdown check
Turboexpander outlet temperature
Blowdown time
N2 purge volume and slug sizing
Propane refrigeration

Volumes and flow

Line fill
Vessel volume
Gas velocity and erosional check
Flare rate and tip velocity

Reference

Pipe schedule
Gas properties
Unit converter tuned to plant work
Plant terms glossary

In the app

PlantHand home screen listing the tools grouped by Hydrates and injection, Pressure and temperature, and Volumes and flow, each with a one-line description of the question it answers — Every tool named by the question it answers, not by its equation

PlantHand hydrate temperature result of 62.3 degrees Fahrenheit with a red warning that the line is 14.3 degrees inside the hydrate region, plus flags for published accuracy limits and a sweet-gas-only constraint — The result, the margin, and every caveat that applies to it, on one card

PlantHand in its dark control-room theme showing the same calculator layout — Dark for the control room, high-contrast light for direct sun

PlantHand pipe schedule reference table showing nominal sizes with outside diameter, wall thickness and inside diameter — Pipe schedule, gas properties and unit conversion, all offline

PlantHand plant terms glossary, searchable and grouped by category — A plant terms glossary for the person who is still learning

Every result names its method

Each calculator names the published correlation behind it and links to the source, so you can read the theory rather than trust a black box. Where a method has a published validity range, a result outside it is flagged. Where a method carries a standing constraint, such as a sweet-gas-only assumption, that is stated with the result.

This is a field estimation tool. It is not engineering design software, it does not produce a certified or stamped result, and it is never the sole basis for a safety-critical decision. Verify every number against your facility’s approved methods.

PlantHand method sheet naming the Towler-Mokhatab gas-gravity correlation, its published source and link, its validity range for specific gravity and pressure, and its limitations including sweet gas only — The method sheet behind a single result: correlation, source, validity range, and what it does not cover

Built for the way the work happens

Dark for the control room, high-contrast light for direct sun
Big touch targets, tested with gloves on
Local atmospheric pressure setting, because 14.696 is not everywhere
Your last inputs are remembered
No account, no analytics, no data collected. Calculators run entirely on your device

A 30-second look at PlantHand

Actual product screenshots with captions. This is a silent screenshot walkthrough, not a live screen recording.

Read the walkthrough transcript

Offline tools for plant work.
Choose the question you need to answer.
Read the result together with its warnings.
Check the named method, range and limitations.
Reference tools are available on the device.
$12.99 USD. iOS 17.0+. Verify field estimates against facility-approved methods.

Straight answers

What does it cost, and which iPhone version does it need?: $12.99 USD one time. iPhone, iOS 17.0 or later. Check the App Store for your region's current price and compatibility.
Does it work without signal?: Yes. Every calculator runs on the device. There is no account, no login, and nothing to sync. The only time it reaches the network is if you tap a method citation, which opens the published source in Safari.
Is there a subscription?: No. One price, everything included, no unlock packs and no recurring charge. Updates to the tools you already have are free.
Where do the numbers come from?: Every calculator names the published correlation behind it and links to the source. You can read the method and its validity range inside the app before you trust a result. Nothing is a black box, and no licensed chart or table is reproduced.
What happens if my inputs are outside the method's range?: You still get a result, with the range violation flagged on the card. The app does not refuse to calculate, because an operator working a real problem needs a number and a warning, not an error message.
Can I use this for engineering design?: No. These are field estimates, the same ones done on a whiteboard, computed faster and more consistently. They are not stamped or certified and should never be the sole basis for a safety-critical decision. Verify against your facility's approved methods.
Is there an Android version?: Not currently. PlantHand is iPhone only.

A practical guide

Read our guide to offline field calculations →

Built by someone who ran the plant

Ten years as a senior operator on stabilizer and cryo units, training and signing off operators before they ran a board. The tools in PlantHand are the ones that got used.

Download on the App Store

iPhone, iOS 17.0 or later · $12.99 USD one time