Paul,
When
codes refer to a company having a "repair WPS", are they saying that
a different test needs to be qualified other than the procedures that have
already been qualified?
If
this is the case, would you record the NDE, hold points,
etc. that are required in the WPS? Sort of like, these are
the steps and sequence of events that are required to take place.
Timothy
C. CWI, CWE
ACCP
Level II VT, PT
ASNT
TC-1A Level II MT, UTT
P.S,
Thanks for the time you've taken over the years to let us ask, argue, talk
through, and debate all the issues we come across. It only makes us better at
what we do.
Tim,
And
all this time I thought I was the only one that would get up at 6am on a
Saturday with welding on the brain (I happened to be calibrating my UT scope
when I got your email).
Let
me concentrate on your first question as it would relate to AWS D1.1 (because
you are right, the Bridge Code is more specific).
D1.1
requires a repair WPS, why would they state that?
In
most manufacturing environments we would have specific WPS’s for specific joint
configurations, materials, positions welded… Let’s imagine the company "PWC
Weld-All" had WPS's for all position, unlimited thickness, Base Metal Group 1 & 2
for Lap, T- (fillets & grooves), V-, Bevel and Square Groove
Joints. Your first impression would be that PWC has his shit together,
right? Now let's say PWC hired his brother (because his Mom made him) to
punch bolt holes in steel with an Iron Worker. Who could mess that
up? Well, his brother did and now you’ve got four 1- inch holes in the
web of a S24x100 I-Beam. The customer insists they be filled. Which
WPS will cover this repair? Since the joint configuration now is a hole
in a plate none of the existing WPS's will apply. A new WPS will need to
be developed which may or may not require testing (dependent on code
requirements).
Here's
another scenario… The base plate of a light pole tower is welded
using FCAW-G. While being erected the customers inspector finds
unacceptable porosity and requires a repair. That repair could be made
using the same procedure used to manufacture the tower, but it wouldn’t be
practical to use FCAW-G, in the field. A procedure would need to be
written (and possibly qualified) to complete this repair using another process
(FCAW-S or SMAW).
One
last scenario… A crack in a weld is discovered in a Bevel-Groove. The
engineer determines it can be repaired. This can typically be done using
the original WPS. While excavating you find this crack extends into base
material. Now your joint configuration will probably be outside the
tolerances of your WPS, so another WPS will need to be written (and possibly
qualified).
Often
times the PQR's you've previously completed will cover the repair WPS, but you
still need to write the new WPS.
As
the engineer I have written many repair WPS's. When I do I will put
language in there that is not typically found in a production WPS. Things
like, “Drill a X/X diameter hole at each tip of the crack to reduce the
chances of growth.” or, “Once discontinuity is removed PT to
insure its complete removal.” or, “MT each weld layer to insure soundness.”
or “Never let my brother touch that machine again.”
So
your repair WPS isn't anything different then any other WPS, you just want to
insure that you've covered all your bases in regard to material, joint
configuration, position before moving forward with the repair.
Ask
me the time and I build you a watch. Sorry about that.
PWC