How many straps do I need to hold a horizontal tank under my vehicle.
If your fitting a gas tank under a vehicle that uses metal straps or hoops that go around the tank, and the weight of the gas tank is held by the metal straps, then the answer is simple - you have to use 3.
There are lots of recognised Autogas tank installation documents, both legal and codes of practice that confirm it, so no matter who's R67 certified gas bottles or gas tanks you use, if the gas cylinder is certified to R67 then your installation has to comply with the legal documents for the installation of LPG tanks to the road going vehiclehat your attachping it to - R67 & BSEN 12979.
Both R67 & 12979 documents not only state that if the straps support the tanks weight, then a minimum of 3 are needed, they are also very specifics on what strap/ hoop material you have to use, bolts, nuts, washer specifications and number of bolts, nuts, washers etc to be used.
Here is the relevant part from the BSEN 12979 regulation document.
1 General requirements
The requirements of this standard for the fixing of LPG containers shall be met if:
the container is secured to the motor vehicle by at least two straps, made from steel with a minimum tensile strength of grade E 235-B according to ISO 630, and
at least two bolts per strap including washers if the body panels at that location are single thickness and the fixing bolts are of class 8.8 according to ISO 898-1,
If the container is installed behind a seat, a total clearance of at least 100 mm in the longitudinal direction of the vehicle shall be provided. This clearance may be provided by adding the distance between the container and the rear panel (if fitted) and the distance between the rear panel and the seat.
If the container straps also support the weight of the container, at least three container straps shall be provided. The container straps shall ensure that the container will not slide, rotate or be dislodged.
A protective material such as felt, leather or plastic shall be put between the container and the straps.