Wasn't it the PECO anchors that came in 304? The Bolt Products BPs have always been 316 I think. We have a dozen PECOs left in a box here and they are visibly less shiny than the BPs. I think it's easy for non-bolters to get mixed up with the P anchor types, so my understanding is these are a 3 generations of BCA 'P' type anchors:
I'm going to start my response by an admission that my memory is failing me and I am not in a position to go back and check all the details. So when DMM announced around 2010 that they were to cease making their P hanger (which has a straight shaft with bent ends). BCA brought up the remaining stock. That kept us going for a few years.
We then started to look for an alternative and an offer was made to us to get batch made in China to the same design. The first batch looked OK but had a problem so a second batch was made. That also had a problem which made us reject the offer. These were the PECO anchors. (See BCA E&T minutes 8/10/11.)
We were then pointed to Bolt Products twisted shaft P anchor (BP anchor). We ordered a trial batch which proved OK. It is not clear to me how or why but we then received a batch of BP anchors made in 304SS. This was at odds with our assessment that we should use 316SS anchors in caves except in high chloride areas such as sea cliffs where an even more Chloride Stress Corrosion Cracking (CSCC) resistant material was required. So we retrieved the 304SS BP anchors (though I fear a few may have been placed) and then acquired 316SS BP anchors. (See BCA E&T minutes 10/11/13.) Subsequently we stepped back and accepted that 304SS BP anchors could be used in agreed locations. (See BCA E&T minutes 5/4/14)
Simon Wilson developed the IC anchor around 2014 and was accepted in 2015. Because of manufacturing constraints, IC anchors were initialy only deployed in the North. But as I recall, thanks to improvements in the manufacturing process, the CNCC agreed to their deployment elsewhere a few years ago.
As I recall, a trial was made with a titanium anchor but this failed. I do not recall if any further work was done by BCA E&T in this area.
If you still have PECO anchors then you should dispose of them. The reason for their rejection was that several in the test batches failed at low forces by metal failure rather than the normal failure mode of extraction from the resin. That makes them even more prone to CSCC (C as in caustic not as in council).
There was also fun with the choice of resin which went through a lot of changes before 'settling down' to the Fischer V 360 S resin which I presume remains the choice to this day.
Another point which arose during that time was routine pull testing of anchors in line with that recommended for EN 795 PPE anchors. What we did not realise is that the heads of the DMM P anchor, the PECO anchor, the BP anchor and the IC anchor all flex at or below 6 kN. So when we got alerts reporting defective anchors in cave due to cracked resin, we ceased the practice. But I recall that DCA claimed to be able to apply a 6kN force without impacting the resin, though how remains a mystery to me.
We also did away with a routine visual inspection program to just rely upon reports from users. And the user inspection criteria was subject to debate when we found that people could not differentiate between movement in their fingers and movement in the anchor when twisting an anchor. (Answer - use a small bar to test for anchor movement.)
I am afraid that I am unable to attend the forum to provide an "old fart's memory" of the past 10 plus years of work on anchors which I observed and participated in. But I did try to ensure the BCA E&T minutes recorded much of the detail and I should have a lot more records on my back up hard drive if any one wishes to delve. Have a good time.
cncc.org.uk
