Contents
Hard-to-Measure Parts, Liquids and Sites

Offline, Air-Gapped and Secure-Site Contact Angle Measurement: Measure Without a Network, on a Device Your IT Team Controls

Defense, aerospace, semiconductor and electronics sites often ban cloud software and control every phone and camera. The Dropometer measures contact angle and surface tension with no network connection, and its apps can run on a phone your IT team manages. Your security office still decides what may enter each area.

Who this is for: Quality, coating and process teams at defense, aerospace, semiconductor and electronics sites, and the IT and security staff who approve their equipment.

Where it fits: Coating and surface checks inside controlled buildings, isolated networks or cleanrooms, where sending samples or data out is slow or not allowed.

What it does not do: It does not carry any security approval or compliance status. Many classified areas prohibit camera equipped devices outright.

Method
Sessile drop contact angle and pendant drop surface tension, analysed on the phone with no network
Standard
Contact angle follows ASTM D8597 practice; site security rules are set by your security office, not by this instrument
Setup
About 2 minutes
Book a 15 minute demo Request a quote
Internet security
Why it matters

Why secure sites need a different measurement setup

No network

is needed to measure. The internet is needed once, to activate the app licences, and then measurement runs offline on the phone.

Droplet Lab, aerospace and defense case study, 2025

PSO and AO

approval is required before mission essential government or contractor owned portable electronic devices enter a Special Access Program facility; waivers must be in writing.

DoD Manual 5205.07 Volume 3, Enclosure 3, paragraph 11

Visual inspection

by a foreign person that reveals technical data counts as a release under the ITAR and the EAR, and ITAR technical data includes photographs, so drop images may need control.

22 CFR 120.33 and 120.56; 15 CFR 734.15

Sources: Droplet Lab aerospace and defense oleophobic coating case study; DoD Manual 5205.07 Volume 3, Change 3, 2020; 22 CFR 120.33 and 120.56 (ITAR); 15 CFR 734.15 (EAR). Figures and rules come from these sources, not from Droplet Lab measurements.

Quick reference

What offline measurement does and what it does not

A quick reference for secure site teams checking fit before reading further.

Evidence Box

Problem this solves

Contact angle or surface tension checks needed inside a controlled building, where cloud software is not allowed, networks are isolated and every device needs approval.

How it works offline

Drop images are captured and analysed on the phone. Measuring needs no internet connection; only licence activation does.

Peer reviewed method

The Dropometer drop shape method was validated against a KRUSS DSA100E in two peer reviewed papers, in Review of Scientific Instruments and Colloids and Surfaces A.

Customer case study

A Fortune Global 500 aerospace and defense company runs the Dropometer apps on an iPhone its IT team assigned, tracks and can wipe, as its security review required.

Rules that apply

DoD and intelligence community rules restrict recording and transmitting devices in secure spaces; export rules treat images of controlled items with care.

Honest limit

We cannot approve the device for your site. Your security office decides, and some areas will not allow any camera equipped device.

Who this is for

What secure site question are you trying to answer?

Pick the card closest to your role. Each one points to the part of this page that answers it.

Quality manager

Customers ask for contact angle proof on coated parts, but your site cannot send parts or data out easily. An instrument that measures on site, offline, keeps the check and the record inside your building.

Ask your security office before ordering, not after.

IT or security officer

You need to know whether the device connects to a network, whether the software needs the internet and who controls the phone. Measurement runs offline, and the apps can run on a phone your team manages, tracks and can wipe.

Plan licence activation before the phone enters the controlled area.

Process or R&D engineer

You work in a cleanroom, a test cell or a lab on an isolated network. A portable kit with local analysis lets you measure at the bench without a networked PC or a cloud account.

Check your cleanroom rules for phones, cameras and wipe down.
Fit check

Is this the right setup for your site?

It measures offline on a phone. Whether that phone may enter your area is your site's decision.

Good fit if

Your site does not allow cloud software for test data.
Your network is isolated or air gapped.
Your IT team can supply and manage a phone for the apps.
You need contact angle or surface tension on site, not at an outside lab.
You need to set the instrument up yourself from a video.

Less relevant if

Your area prohibits all camera equipped devices with no exception.
You need results to flow automatically into a networked system.
You need a certified, accredited security configuration from the supplier.
You cannot activate licences outside the controlled area.
Summary

How the Dropometer works at offline and secure sites

The answer in under a minute.

The Dropometer captures and analyses drop images on the phone, so measuring contact angle and surface tension needs no network connection; only licence activation needs the internet, once. The apps can run on a phone your IT team manages. Your security office decides whether that phone may enter each area and how data leaves.

The Dropometer contact angle and surface tension kit is portable. An aerospace and defense case study shows the apps on a company managed iPhone at a secure facility, and a plating chemistry case study describes the offline analysis. The ASTM D8597 page covers portable contact angle measurement, and our portable versus benchtop guide compares the options.

Expert Quote

Expert perspective on measuring where the part is

“

A contact angle is a thermodynamic property: fix the liquid and the solid and the same angle appears whether the drop sits on a plate or climbs a capillary.

Dr. Alidad Amirfazli

Professor, Department of Mechanical Engineering, York University; Co-founder, Scientific Advisor, Droplet Lab

The problem

Why measuring at a secure site is hard

Many measurement instruments assume a networked PC, a vendor cloud account or a camera that can go wherever the operator goes. Secure sites assume the opposite. NIST defines portable electronic devices as devices that can store, record or transmit text, images, video or audio, and cellular telephones are the first example. DoD and intelligence community rules restrict those devices in secure spaces. In Special Access Program facilities, mission essential government or contractor owned devices need written approval from named authorities, and other devices are prohibited. Navy instructions and research cleanrooms also limit cameras and phones, and some require permits, wipe down and approved devices. Data adds a second problem. Under the ITAR, technical data includes photographs, and visual inspection by a foreign person can count as a release; the EAR uses similar wording. Defense contracts also restrict cloud services that hold covered information. So a team that needs contact angle proof on a coated part may be unable to send the part out, unable to upload the images, and unsure whether any phone based instrument can come in. The answer depends on the site, and the security office decides.

Coated parts wait weeks for an outside lab because shipping needs review.
IT will not allow instrument software that needs the internet.
Security asks who controls the phone and where images are stored.
Cleanroom rules limit cameras and personal phones.
Customers still ask for contact angle results as proof of quality.
Troubleshooting

Common blockers at secure sites and what to do

Why:

  • Many instruments rely on cloud accounts or online licence checks.

How to detect:

  • IT asks whether the software works with networks disabled.

Corrective action:

The Dropometer measures offline; activate the licences once before the phone enters the area. The aerospace and defense case study shows how one site did it.

Why:

  • A supplier phone may not meet the site's device management rules.

How to detect:

  • Security asks who can track, lock or wipe the device.

Corrective action:

  • Run the apps on a company managed phone, or use the supplied Android phone with location tracking, remote lock and remote erase turned on.

Why:

  • Secure spaces often prohibit recording devices except approved, mission essential ones.

How to detect:

  • The area's rules name cameras or portable electronic devices.

Corrective action:

  • Ask the security office whether a mission essential approval is possible, or measure in an adjacent controlled lab.

Why:

  • Images of controlled parts may be technical data, and transfers need approval.

How to detect:

  • Results are needed in a report outside the controlled area.

Corrective action:

  • Keep images and results on the managed phone, and use only the transfer route your site approves.

Why:

  • An offline phone cannot receive app updates or activate a licence.

How to detect:

  • The app asks for activation or an update inside the area.

Corrective action:

  • Activate and update outside the area, then disable networks before entry.

Why:

Readings must match readings taken elsewhere. Our guide to reproducible contact angle measurement covers fair comparisons.

How to detect:

  • A reference sample reads differently on site.

Corrective action:

Level the stage with the bubble level, set scale from the needle diameter and compare with our contact angle reference values.

Need answers for your security review?

Send us your site's device questions, and we will answer them on a call.

Book a 15 minute demo
Lab records

What a secure site measurement record contains

Each check produces a record kept on the managed phone or in your approved record system. It can feed into your existing quality records.

Device

Approved device ID, network state and who manages it.

Sample

Part or coupon, coating and lot, described at the level your site allows.

Method settings

Liquid, drop volume, read time, temperature and humidity.

Readings

Contact angle or surface tension, with median and spread.

Data location

Where the images and results are stored and any approved transfer.

Drop images

Automatic edge and baseline detection gives the same reading from the same image, so a reviewer can recheck any result.

Measurements

What to measure at a secure site

Coating

Water and oil contact angle on coated parts

Why it matters: Customers use multi liquid contact angle as proof that hydrophobic and oleophobic coatings work.

How to interpret: Pass and fail limits come from customer drawings or your own correlation study, not from a general threshold.

When it is not enough: It does not prove durability or coating thickness.

Liquids

Surface tension of process liquids

Why it matters: Cleaners, primers and coatings change as they age or are contaminated.

How to interpret: Compare with a reference lot measured the same way.

When it is not enough: It is an equilibrium value, not a millisecond dynamic value.

Readiness

Water contact angle before coating or bonding

Why it matters: It shows whether cleaning or treatment worked on the part itself.

How to interpret: Set gates from parts that passed and failed your downstream tests.

When it is not enough: It does not replace adhesion or environmental tests.

Method

Reference sample on site

Why it matters: It shows the offline setup reads the same as your other sites.

How to interpret: Measure the same reference sample at each site and session.

When it is not enough: It does not detect problems that only appear on real parts.

Validation

Validated measurement approach for secure sites

How the Dropometer itself has been validated, and how a secure site set it up.

Peer reviewed method

The Dropometer drop shape method is published in Review of Scientific Instruments and Colloids and Surfaces A. Contact angle was validated against a KRUSS DSA100E, with a published accuracy of 0.35°.

See the validation papers

Customer evidence at a secure facility

A thin film coating team at a Fortune Global 500 aerospace and defense company runs the Dropometer apps on an iPhone its IT team assigned, as its security review required. Droplet Lab confirmed that measuring needs no network. The engineer set it up from a video and took a proper measurement without a site visit.

Read the case study
QC Protocol

How to set up offline measurement at a secure site

Six steps per site. Agree each one with your security office first.

1

Agree the device

Decide with IT and security whether the apps run on a company managed phone or the supplied phone with remote lock and erase.

2

Activate outside

Activate the app licences and update the apps outside the controlled area.

3

Disable networks

Turn networks off before the phone and kit enter the area.

4

Calibrate

Level the stage with its bubble level and set the image scale from the needle diameter. Our wettability glossary entry explains what the angle shows.

5

Measure and record

Run contact angle or surface tension by your method lock, and keep images on the device. Our contact angle measurement guide covers the method.

6

Follow the data rule

Move results out only by the route your security office approves.

We completed our gage R&R study on the unit and it performed very well.

Brandon Barbee

Corporate Quality Engineer, Zeus Industries, Polymer Manufacturing

Download the secure site measurement SOP

A two page SOP you can adapt for your site, with device and network decisions, the method lock, offline steps, a troubleshooting table and a record sheet.

Contact angle measurement with the Dropometer

Example output

Example secure site setup and measurement log

Example data only. Your site's decisions and values will differ.

How to read this log

Each measurement is tied to the approved device, its network state and where the data stayed. The coating results are compared with the customer drawing limit. Our aviation and space guide covers coated aerospace parts.

Example secure site measurement log

Date Device Network Sample Liquid Contact angle (°) Data location Result
Day 1 Managed phone A Off Coupon 1 Water 112 On device Pass
Day 1 Managed phone A Off Coupon 1 Oil 71 On device Pass
Day 1 Managed phone A Off Coupon 2 Oil 48 On device Fail; recoat
Day 2 Managed phone A Off Reference Water 105 On device Method check

Example data, not customer data. Oleophobic coated coupons; 5 µL drops; median of 5 drops per liquid.

Signal order

The order to check things before measuring on site

Check these in order. Each one clears a blocker before you look at the next.

1

Area rules

Confirms whether any camera device may enter.

2

Device control

Confirms who manages, tracks and can wipe the phone.

3

Activation and network

Confirms licences are active and networks are off.

4

Method and reference

Confirms the setup reads like your other sites.

FAQ

Common questions about offline and secure site measurement

Questions IT, security and quality teams ask before ordering.

Does the Dropometer need the internet?

Not to measure. Drop images are captured and analysed on the phone, so contact angle and surface tension measurements run with networks off. The internet is needed once, to activate the app licences, and later for app updates if you choose to install them outside the controlled area.

Can the apps run on our own phone?

Yes, on a supported phone your IT team manages. At one aerospace and defense company the apps run on an iPhone that IT assigned, tracks and can wipe. Some modules can arrive on one platform before the other, so check the current app list with us. The case study describes that setup.

Is it approved for SCIFs or SAP facilities?

No supplier can make that decision. DoD rules for Special Access Program facilities prohibit portable electronic devices except approved, mission essential government or contractor owned devices, which need PSO and AO approval. Many classified areas will not allow any camera equipped device. Your security office decides.

Where are images and results stored?

On the phone. The site controls that device and decides whether and how data leaves. Images can also be saved to cloud storage of the user's choice, but secure sites usually keep that turned off, so results stay inside the area.

Do drop images count as technical data?

They can. Under the ITAR, technical data includes photographs, and visual inspection by a foreign person that reveals technical data counts as a release; the EAR uses similar wording. Your export control officer decides how drop images of controlled parts are handled and who may view them.

Does working offline make us CMMC or NIST 800-171 compliant?

No. Offline measurement avoids putting test data into a cloud service, but compliance depends on your whole system and contract. NIST SP 800-171 covers mobile devices, wireless access and media use, and the CMMC program status has changed during 2026. Ask your compliance lead.

Can it be used in a cleanroom?

Often, subject to your cleanroom rules. Research cleanrooms we reviewed restrict personal phones and photography, and ask for permits, approved devices and wipe down before entry. Check your own protocol, and plan a dedicated managed phone and cleaning steps for the kit.

How do we compare results with other sites?

Use the same method lock at every site: liquid, drop volume, read time and levelling. Measure a shared reference sample each session, and compare with our contact angle reference values. Our portable versus benchtop guide covers how portable setups compare.

Business impact

What changes when you measure on site, offline

Typical changes in how teams work. Benchmarks are given only where a published source exists.

Before and with on site offline measurement

Metric Before Dropometer With Dropometer Indicative Benchmark
Where samples are measured Sent to an outside lab after review Measured on site No published benchmark; track on your own jobs
Network dependence Software needs internet or cloud Measures with networks off Internet needed once for licence activation (Droplet Lab case study)
Device control Supplier controlled device Company managed phone Apps on a company iPhone IT can track and wipe (Droplet Lab case study)
Image handling Images leave with the samples Images stay on the managed device Photographs can be ITAR technical data (22 CFR 120.33)

Bring your security questions

Tell us your site's device and data rules. We will walk through the setup on a call.

Book a 15 minute demo

Estimate the value of measuring on site instead of sending samples out

Enter your own numbers. The result is an estimate, not a Droplet Lab claim.

On site measurement estimate

Estimate the value of measuring on site instead of sending samples out.

Each Dropometer unit is US$5,000; the default models one unit.
Your own cost per sample, including shipping and any export review.
Packing, review, shipping, follow up and waiting time per sample.
No published benchmark. Use your own estimate and start low if unsure.

Result

~0
Candidates saved per month
~0
Monthly savings
~0
Payback period
~0
First year net benefit

Monthly savings = materials saved + technician time saved from reduced iterations.

Limits

What this setup cannot do for a secure site

Honest limits, so you know what still needs your security office.

It carries no security approval or compliance status.
Some areas prohibit all camera equipped devices.
Licence activation needs internet once.
App updates must happen outside the area.
Module availability can differ between phone platforms.
Results do not flow automatically into networked systems.

The Dropometer measures offline and can run on a phone your IT team manages. Device approval, export control decisions, data transfer rules and compliance with any security program stay with your organization.

Book a 15 minute demo Request a quote
Related

Standards, evidence and related on site workflows

These pages cover portable contact angle measurement, customer setups at controlled sites and related on site checks.

Standard

ASTM D8597

Contact angle with portable goniometers.

View standard

Case study

Aerospace and defense company

Dropometer apps on a company managed iPhone at a secure site.

Read case study

Case study

Plating chemistry maker

Offline analysis on the phone at two R&D sites.

Read case study

Instrument

Dropometer

Contact angle and surface tension, portable.

View product

Related use case

Hard to measure parts, liquids and sites

All hard to measure use cases in one place.

View Page

Related use case

Wetting checks on large parts

Measuring in place on parts that cannot move.

View Page

Related use case

Plated coating wettability

Wettability and corrosion of plated coatings.

View Page

Guide

Portable vs benchtop

Choosing between portable and benchtop goniometers.

Read guide

How this page was created

Editorial and technical transparency notes for this page.

Transparency Details 4 checklist items
01

Drafting assistance

Drafted with Claude Opus 5.5 (Anthropic) using web search for sources, then edited by the Droplet Lab team.

02

Technical review

Reviewed and edited for technical accuracy by the Droplet Lab Team.

03

Verification steps

Standard identifiers, units, thresholds and key procedural claims are checked against cited sources before publication.

04

Updates

Reviewed every 12 months or when the underlying method changes.

Report a correction

Spotted an issue in this summary? Send a correction request and our team will review it.

Correction Request

We work hard to keep this page accurate and up to date. If you spot an error (wrong revision/year, missing requirement, incorrect interpretation, or broken link), tell us and we'll review it.

Contact us to report a correction
Sources

References

1.
DoD Manual 5205.07 Volume 3, April 23, 2015, Change 3, December 8, 2020. Enclosure 3, paragraph 11. https://www.esd.whs.mil/Portals/54/Documents/DD/issuances/dodm/520507_vol03.PDF
2.
DoD Manual 5200.01 Volume 3, Change 3, July 28, 2020. Enclosure 2, paragraph 16. https://www.esd.whs.mil/Portals/54/Documents/DD/issuances/dodm/520001m_vol3.pdf
3.
ICD 705, Sensitive Compartmented Information Facilities, May 26, 2010. https://archive.dni.gov/files/documents/ICD/ICD-705-SCIFs.pdf
4.
Technical Specifications for Construction and Management of Sensitive Compartmented Information Facilities, version 1.5, 2020. Chapter 10, portable electronic devices. https://archive.dni.gov/files/Governance/IC-Tech-Specs-for-Const-and-Mgmt-of-SCIFs-v15.pdf
5.
NAVSEAINST 2200.1, portable electronic device policy, February 2, 2015. https://www.navsea.navy.mil/Portals/103/Documents/NAVSEAINST%202200.1,%20PED%20Policy%20-%202%20Feb%2015.pdf
6.
NIST glossary: portable electronic device (CNSSI 4009-2022). https://csrc.nist.gov/glossary/term/portable_electronic_device
7.
NIST glossary: air gap (CNSSI 4009-2022). https://csrc.nist.gov/glossary/term/air_gap
8.
NIST SP 800-171 Rev. 3, Protecting Controlled Unclassified Information in Nonfederal Systems and Organizations, May 14, 2024. https://csrc.nist.gov/pubs/sp/800/171/r3/final
9.
NIST SP 800-82 Rev. 3, Guide to Operational Technology Security, September 28, 2023. https://csrc.nist.gov/pubs/sp/800/82/r3/final
10.
22 CFR 120.33, technical data (ITAR). https://www.ecfr.gov/current/title-22/chapter-I/subchapter-M/part-120/subpart-C/section-120.33
11.
22 CFR 120.56, release (ITAR). https://www.ecfr.gov/current/title-22/chapter-I/subchapter-M/part-120/subpart-C/section-120.56
12.
15 CFR 734.15, release (EAR). https://www.ecfr.gov/current/title-15/subtitle-B/chapter-VII/subchapter-C/part-734/section-734.15
13.
DFARS 252.204-7012 (May 2024). https://www.ecfr.gov/current/title-48/chapter-2/subchapter-H/part-252/subpart-252.2/section-252.204-7012
14.
DFARS 252.239-7010 (January 2023). https://www.ecfr.gov/current/title-48/chapter-2/subchapter-H/part-252/subpart-252.2/section-252.239-7010
15.
DoD CIO, about CMMC (program status, 2026). https://dodcio.defense.gov/CMMC/About/
16.
ISO 14644-1:2015, cleanrooms and associated controlled environments, part 1: classification of air cleanliness by particle concentration. https://www.iso.org/standard/53394.html
17.
NIST CNST NanoFab safety manual, 2026. https://www.nist.gov/document/cnst-nanofab-safety-manual
18.
NY CREATES OPS-00001 Rev 26, cleanroom protocol requirements, June 2024. https://ny-creates.org/wp-content/uploads/OPS-00001-R26-Cleanroom-Protocol-Requirements.pdf
19.
Chen, X. et al. Contact angle measurement with a smartphone. Review of Scientific Instruments 89(3):035117, 2018. https://pubs.aip.org/aip/rsi/article-abstract/89/3/035117/368179/Contact-angle-measurement-with-a-smartphone
20.
Surface tension measurement with a smartphone using a pendant drop. Colloids and Surfaces A: Physicochemical and Engineering Aspects. https://www.sciencedirect.com/science/article/abs/pii/S0927775717307744
21.
Droplet Lab validation papers
22.
Customer publications that cite the Dropometer
23.
Contact angle measurement guide
24.
Semiconductors guide