Technical Consulting · Hazardous Location Signaling · Fire & Life Safety · Gas Detection
Notification and gas detection design for hazardous locations.
Independent design consulting from a fire alarm signaling specialist with more than 40 years in the industry. No products sold — the recommendation is based on the application, not a product line.
Services
Design support where the signaling has to work in a classified area.
Hazardous location signaling
Horn, strobe, speaker and beacon selection for Class I and Class II, Division 1 and 2 areas — matching the device listing to the area classification and the fire alarm application.
Fire alarm notification design
Audible and visible coverage under NFPA 72 — dB(A) at 10 ft against ambient, candela to UL 1971, and NAC voltage-drop calculations held to a 10–15% margin over device minimums.
Gas detection systems
Detection layout and alarm signaling for gas detection systems, including how detector outputs drive warning devices in the same classified space.
Specification & submittal review
A second set of eyes on specs, device schedules and submittals — catching non-hazloc parts in hazloc areas, wrong listing basis, and output figures measured to the wrong standard.
Approach
Published figures, shown math, no product bias.
Every recommendation traces back to a datasheet, a listing, or a code section you can check yourself.
Vendor-neutral
Rhett Day Consulting sells no products and takes no commissions. The device that fits the application is the one that gets specified.
Datasheet figures govern
Output, current draw and operating voltage come from the manufacturer's published data — not price-list summaries — and every check against a limit is labeled clear or over.
Designed with margin
Circuits are laid out with headroom over device minimums rather than running on the edge of a published maximum.
Standards & listings
Working fluency in the codes that govern the job.
About
Rhett Day
Rhett Day has worked in the fire alarm industry since 1980, when he founded A&R Systems. In 1995 he founded The Signal Source, a specialty distributor focused on hazardous location fire alarm signaling, and built it into a go-to resource for contractors working in classified areas.
Rhett Day Consulting brings that experience directly to designers, contractors and owners — independent of any manufacturer — for notification and gas detection projects where the signaling has to be right the first time.
Full background and career timeline →Rhett Day Consulting provides design consulting services. Final design approval rests with the designer of record and the authority having jurisdiction.
Have a classified area to cover?
Send the area classification, the drawings you have, and what the system needs to do. You'll get a straight answer on scope.