Thursday, October 1, 2015

Detecting Fire and CO

We learned about fire detection at an Annapolis Sail & Power Squadron meeting this year, presented by John McDevitt. John has worked in the past with fire departments and participates in NFPA (National Fire Prevention Association) and ABYC standards writing. He said that most standards are written for fire suppression, which means that a fire exists and you're trying to put it out. That's likely to be a losing proposition on a fiberglass boat. His view was the fire detection was more useful.

FirstAlert Onelink Smoke & CO Alarms
He recommended wireless smoke detectors to provide early alert to a developing fire situation and showed us the Onelink Wireless smoke detectors in operation. These detectors communicate with one another wirelessly and when any one of them alarms, they all alarm. The feature that he likes is that you can program the alarm to verbally announce the location of the alarming device. These devices are built for home use, with verbal announcements like "Livingroom", "Child's Bedroom", or "Basement".

We just installed a genset on LUX and are also concerned about Carbon Monoxide. While the genset is diesel powered and has a lower threat of CO, it doesn't eliminate the threat. So we started looking for detectors and found these: "Onelink Wireless Talking Battery Operated Smoke & Carbon Monoxide Alarm SCO501B2 - 2pk", available from Amazon. They are around $100 for a pair.

We had eight places to put them: Four cabins, two engine rooms salon, and forward locker with the genset. The cabins are small, so we felt that mounting them on the ceiling was acceptable and would still alert us in a CO situation even though CO is heavier than clean air. We mounted them to the inboard wall in the engine compartments. Each alarm is programmed with a different verbal location.

Cabin Mount Location
Engine Room Location
We then made up a laminated "cheat sheet" for each cabin and for the salon, showing what location corresponds with each alarm's verbal announcement.

Alarm Verbal Announcement Cheat Sheet
We feel that the addition of smoke and CO alarms on board will make us safer.

Generating Light without a Fire

Much to our surprise, we found that some of the fluorescent light fixtures in the cabins on LUX were overheating. One had been accidentally left on during part of the winter and we're fortunate that it didn't start a fire.

Evidence of Overheating

These lights are Labcraft and consume up to 1.2 Amps, depending on how many bulbs are installed. Replacing the offending bulb was the short-term fix, but we needed something that would never overheat, even if accidentally left on for months at a time. The light fixtures are nice, so we decided to install LEDs in them.

We found FlexFire LEDs, (ColorBright Natural White - Spec Sheet) which were reported to be very bright. They come in a roll and you cut off as many as you need, in 1-inch chunks. They aren't the cheapest around, but they seem to be much brighter than the other LEDs we've seen. 
The FlexFire LED Instruction Sheet
Unsoldering the Board
We started the modification by removing the label and unsoldering the board from the switch - the two points labeled with arrows in the picture. The board has several connections to the lights and a bunch of discrete components. We clipped the wires and unsoldered most of the components. The transformer and a couple of capacitors were left because they don't affect the operation of our modification.
Ballast Board With Components

Ballast Board Without Components
A hole was drilled between the electronics compartment and the light bulb area and wires routed to power the LEDs. A jumper was installed on the PC board to connect the +12v and ground connections to the switch.
Jumper the Power Leads to the Switch

Next, cut the LED strips to the length that fits where the lights used to be located. We cut 11 inch strips of LEDs. Only cut where it says to cut. There are two small solder pads that are obvious if you look carefully at the strip.
Sizing the LED Strips

Solder connecting wires to each LED strip and then connect them to the power leads that connect through to the PC board. Then remove the adhesive paper backing and stick them into the fixture. The connections to the power leads were soldered and covered with heat shrink tubing.
Soldering Wires to the LED Strips

They Are BRIGHT!
The new LED lights are BRIGHT! They seem much brighter than the old fluorescent bulbs and consume 0.4A per fixture. We converted four of the lights (one in each cabin) in a few hours.

After writing up this post, I discovered the Mike Boyd has an excellent pair of writeups on the subject: