Smart questions
Smart answers
Smart people
Join Eng-Tips Forums
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Member Login




Remember Me
Forgot Password?
Join Us!

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips now!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

Join Eng-Tips
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.
Jobs from Indeed

Link To This Forum!

Partner Button
Add Stickiness To Your Site By Linking To This Professionally Managed Technical Forum.
Just copy and paste the
code below into your site.

Barcol hardness of in-serivce FRP equipmentHelpful Member!(2) 

TankInspection1 (Industrial) (OP)
7 Jul 06 13:58
I am attempting to evaluate Barcol hardness results from a FRP tank that has been in sodium chlorate solution service since 1995. The tank was constructed with inner corrosion barrier of DERAKANE 411 reinforced with (2) ply C-glass surface Mat.

From what I can ascertain the barcol hardness was approximately 35 when originally constructed and my average barcol hardness at this time is 39.78

What hardness value would indicate a potential problem for  this type of equipment and service?

Thanks in advance for any assistance
Helpful Member!  Oceania (Mechanical)
14 Jul 06 3:49
The normal problem of corrosion is shown in part by a reduction in Barcol hardness (I assume you are undertaking the inspection to the appropriate standard). I would check the expected hardness against the manufacturers data for the cure system that was used. However it is known that full cure is not always achieved during construction and depending on the tank temperature the VE can continue to cure and achieve higher results once in service. (You can get higher results by hitting glass fibres). You don't say what the concentration or temperature is, providing it is low temperature <50DegC and the Sodium Chlorate is stable then I would expect there to be very little attack on the liner. In which case 32-40 Barcol could be a reasonable result.
Helpful Member!  gvanbeek (Mechanical)
21 Jul 06 13:18
Having personally inspected numerous chlorate tanks, I can tell you that it is common for the barcols to increase after being put into service.  

Most chlorate tanks are not post cured prior to being placed into service.  Most Sodium Chlorate tanks (and especially those used for unloading crystal from rail cars) operate at temperatures > 165F.  This will provide a post cure during the first few days of service.

Because the chlorate is not typically agressive to the resin the post cure from service increases the barcol as there is further crosslinking that is taking place.  It appears that you are not having corrosive attack of the resin, which typically lowers the barcol rather than the increase you have seen.
EdClymer (Mechanical)
29 Jul 06 5:15


I agree: state of cure is dependent on time and temperature.
unless specific post-cure has been applied (in which case the records should show the Barcol value)

Note. All laboratory Barcol values are taken on a cast resin, unless the needle hits pure resin on the laminate a false value is created. Best to do many tests

Regards

Ed Clymer
Resinfab & Associates
England

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close