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6.4.2
Destructive weld test (Peel test)
Before starting work on site (morning and afternoon) and
whenever there has been a change in the weather conditions, the
welding parameters have to be verified and adjusted accordingly
by carrying out a welding test. This is a site test and samples are
torn by hand in the absence of a calibrated peel tester in the lab.
Width of the sample: >20 mm
The requirement for a good weld is that the peel resistance is
greater than the required inter-laminar adhesion between the top
and bottom PVC layers.
The peel test (by hand) shall not be carried out before the sample
has cooled down to ambient temperature. Prior to performing
the peel test, cut the sample material into strips 20 mm wide.
The samples shall he torn by hand in lengthwise and crosswise
direction respectively. When there is a delamination of either the
top or bottom sheet the requirement is fulfilled and the welding
parameters are set correctly. The delamination means a controlled
destruction of the product.
When the seam peels off without a delamination of the
membrane layers, it is indicated that the welding parameters
were insufficient. A visual check can give a lead to whether:
• The air temperature was too low
• The traction of the machine was too great
• The pressure was not big enough
• The material itself was too cold or damp.
New tests must be carried on cooled samples until the correct
parameters can be set for the next period of work.
The peel test can also performed directly on the construction site
using an electrical tensiometer. The advantage is to determine
the welding strength and/or the peel force as well as the
corresponding elongation data.
6.5
Sealing of seams
Seam edges of Monarplan® waterproofing membranes, whether
backed, unbacked or reinforced, do not require sealing. The sealing
gives however additional protection for the seam edge. After
seam testing, the seam edges can be sealed with approx. 20 g (25
ml) Monarplan® liquid PVC per meter welded seam; i.e. approx.
100 m of seam edges with 2.5 l Monarplan® liquid PVC. The seam
edges have to be dry and clean.
6.6 Welding of aged (weathered) membranes
Generally, weathered membranes may be fused with new
material on site after years. Necessary technological changes
(closing of roof penetrations, flashing of new penetrations to
the existing roof sealing) and repairs of damage resulting from
inexpert handling, can be carried out with the same material.
Where it is to overlap with the new material, the weathered
surface must be thoroughly cleaned with low-surface-tension
water (water with dish- washing liquid), if necessary, after drying,
with Monarplan® cleaner for waterproofing membranes.
The overlapping surfaces must be absolutely dry and clean and
can be welded with hot air.
Test welds are obligatory!
Weathered unbacked membranes - if the underneath is clean -
can also be welded to underlying new material. Humidity and
moisture trapped under the membranes may impair weldability.
The described pretreatment, particularly the drying, is essential
for the welding area.
Monarplan
®
Installation manual
062014V1
20
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