+1 (713) 555-0100Emergency line · 24 / 7
HOUSTON · PASADENA
COMPLIANCE →Request a quote
01 / INSIGHTS

Field notes, not sales copy.

Written by the engineers who design, commission, and maintain these systems — the numbers and the mistakes we'd want to know about before they're ours to fix.

How many air changes per hour is actually enough?
LATEST · DESIGN

How many air changes per hour is actually enough?

ACH gets treated like a badge of honour on a spec sheet. It should be a design output, not the number you start from.

PUBLISHED
AUG 28, 2026
READ TIME
3 min read
AUTHOR
David Alvarez, P.E.
Read the full note
02 / MORE FIELD NOTES
07 ARTICLES
How to read a filter integrity certificate
COMPLIANCE
AUG 14, 2026 · 3 min read

How to read a filter integrity certificate

A factory efficiency certificate tells you about the filter. An installed leak scan tells you about the room it went into.

Sarah Kowalski, P.E.
Sarah Kowalski, P.E.READ →
Why cascade pressure drifts in the first year after handover
MAINTENANCE
JUL 30, 2026 · 3 min read

Why cascade pressure drifts in the first year after handover

The pressure cascade you commissioned and the one you are running eighteen months later are rarely the same, and it is rarely dramatic.

Kevin Ostrowski
Kevin OstrowskiREAD →
DX or chilled water: choosing an AHU for a classified space
DESIGN
JUL 16, 2026 · 3 min read

DX or chilled water: choosing an AHU for a classified space

The right answer depends less on tonnage and more on how tightly you have to hold humidity, and whether you already have a chilled water loop.

David Alvarez, P.E.
David Alvarez, P.E.READ →
What actually happens during IQ, OQ, and PQ
COMMISSIONING
JUL 2, 2026 · 3 min read

What actually happens during IQ, OQ, and PQ

Three letters get used almost interchangeably by people who have never sat through one. Each stage answers a different question.

Sarah Kowalski, P.E.
Sarah Kowalski, P.E.READ →
Retro-commissioning a decade-old cleanroom
CASE NOTES
JUN 18, 2026 · 3 min read

Retro-commissioning a decade-old cleanroom

A twelve-year-old Grade C suite had drifted quietly out of spec. Nothing had failed outright — which was exactly the problem.

Marcus Doyle
Marcus DoyleREAD →
21 CFR Part 11 and your environmental monitoring system
COMPLIANCE
JUN 4, 2026 · 3 min read

21 CFR Part 11 and your environmental monitoring system

Most environmental monitoring systems we inspect were bought for the sensors. Few were scoped for what an FDA inspector will actually ask to see.

Sarah Kowalski, P.E.
Sarah Kowalski, P.E.READ →
A filter change programme that survives an audit
MAINTENANCE
MAY 21, 2026 · 3 min read

A filter change programme that survives an audit

A calendar reminder is not a filter change programme. What an auditor wants to see is a trail that proves the room stayed in spec the whole time.

Michael Reyes
Michael ReyesREAD →
NEXT STEP

Send the brief.
Even the rough one.

An engineer reads it and replies within one working day — usually with the two or three questions that decide the price.

Request a quote+1 (713) 555-0100