Burn off tests for ISO

Hi there,

I am a little confused about burn off tests for the ISO rules to meet ISO B scantling rules. Does the sample have to come from the actual laminated yacht? This would obviously be a true representation of achieved fibre weights BUT, what if the yacht is made of different fibres all with different achievable fibre weights? It will be possible to know the average fibre weight but not the individual fibre weights of each material.

I'm then thinking that test panels must be made up but this is not a true reflection of what has been achieved on the yacht......Please help,

Thanks

 

Dont know. I was once involved with the survey of a big composite boat...


The surveyor took several cores ,with a small hole saw, from various locations on the vessel , representing different layup schedules. I don't know if this survey conformed to THE RULES.

 

Table C4b) show that mat,roving,mutliaxial 0/90 have the same mechanical properties for the same fiber content.

So, if your ply is made of only of theses (No sprayed mat, no biaxial +45/-45, no UD), the average fiber weight is enough to use EL-b. You do not need to know each individual ply.

 

ISO 12215 prescribe burn off test if you are not aware of your laminating schedule. If you know your laminating schedule, present to your notified body for plan approval and it will later be verified during the hull inspection

 

How do you know if the vessel was built as designed ?

 

For ISO, El-C , you use tabulated data for fiber content, and 80% of tabulated data for mechanichal properties. You do not do ANY test.

For El-B , you need to check fiber content on samples taken from the actual boat. You need to check some mechanical properties against the tabulated data. If Ok, you can use actual data found for fiber content, and use 100% of tabulated mechanical properties.