Mine are stored in the eyebrow as well. No issue on any survey.
One surveyor did comment to make sure any conduit going down through the boat was plugged so if a leak did occur, it wouldn't find it's way to the bilge. There are a couple of vents cut into the sides of the eyebrow.
That is the setup on mine too.
All penetrations that lead to the cabin are raised 4" above the deck and filled with 5200 around the various wires, Morse cables, propane line, etc.
Vents either rear corners at deck level, no opening windows below the vents.
Louvred doors in front of the tanks,
Survey this year noted the propane installation as "open to atmosphere".
All Good.
I believe the top loading is so when you open the door the propane that may be in the locker will not run out. Propane is heavier than air so with the top loading the propane will remain in the locker and run out through the discharge tube as designed.
I have yet to find any classification society that states the same requirement.
I would appreciate a link to an LPG standard for pleasurecraft from any of the classification societies.
These are what I have researched recently, but you can search more IASC organizations. This thread seems to have evolved into discussing ABYC which apparently is God-Almighty. Perhaps if your insurer is requiring compliance to them, and you cannot do so, then find another insurer!
CHINA CLASSIFICATION SOCIETY 6.3.1.6
http://www.ccs.org.cn/ccswzen/font/fontAction!article.do?articleId=8a808a5b3ee3faf8013eef51dd7004aa
BUREAU VERITAS
Does not specifically address propane in its publication "Rules for the Classification and the Certification of Yachts" but there are sections on fire fighting, appliances, etc. However BV has an entire document for propane fueled vessels which you can read through if you have a lot of spare time.
https://www.veristar.com/portal/veristarinfo/files/sites/veristarinfo/web%20contents/bv-content/generalinfo/giRulesRegulations/bvRules/yachtsrules/documents/4760.5.NR500_2012-03.pdf
http://www.bureauveritas.jp/news/pdf/647-NI_2018-01.pdf
DNV GL 2.2.3
http://rules.dnvgl.com/docs/pdf/dnvgl/ru-yacht/2016-10/DNVGL-RU-YACHT-Pt4Ch11.pdf
ISO 10239:2014 (needs to be purchased)
https://www.iso.org/standard/60148.html
BRITISH STANDARDS BS EN ISO 10239:2000
I just came across this document, summarizing the BS standards which are compliant with the ISO above, and it DOES address side opening lockers, so I may have answered my own previous questions in this thread:
https://www.boatsafetyscheme.org/media/164540/bss%20guide%20chap7.pdf
Yep, you can easily build an air tight, side opening container that will be safe and compliant - and will fit under the eyebrow of many trawlers - of course with drain openings.
I'm curious as to how a side opening container would satisfy ABYC A-1.8.1.4: "LPG Lockers... shall open only from the top".
ABYC says the drain must be "outboard" which is a confusing term.