I have inserted extracts from TG4:11 below to help you along the way; however YOU ALL need to read and understand the whole document.
If you wanna be a scaff you need to know how it works!!
6.1 Preliminary tests
Test load:
All anchor types except nylon anchors shall be loaded in tension to a load of 2 x the working load as applied to the anchor, Nylon anchors should be tested to 3 x working load.
If all test anchors take the test load without slip then the anchor may be used in that base material for the proposed working load. Should any anchor fail to meet the required test load then that fact should be referred back to the person responsible for the anchorage design of the project.
6.2 Proof tests
These are needed to check that anchors to be used in the job have been installed correctly.
They should be carried out on all projects.
This guidance applies to all new jobs and to structures with previously installed anchors.
A sample of anchors to be used shall be tested to a load of 1.25 times the working load; in the case of ties
with a working tensile load of 6.1 kN this means a test load of 7.6kN and where a tie load of 12.2 kN is required
the proof load is 15.3kN. The pass criterion is that no significant movement of the anchor is apparent; a visual check only is sufficient.
A minimum of 3 anchors shall be tested and at least 5% (1 in 20) chosen at random and spread evenly
throughout the whole job.
The minimum number (3) applies to every discreet area where:
(a) different fixings may have been used,
(b) the base material is different
(c) the condition of the base material has been affected by different weather conditions on a different
elevation or
(d) a different team of installers have worked.
All Factors quoted here, including those used to determine the
test loads, are specific to short term or temporary uses
including scaffolding and should not be used for other long
term applications for which higher factors are needed, see [12].
Factors used for nylon anchors are different because of
“Creep”[10].
All anchors that have been proof loaded should be clearly identified with a tag showing the date of test and the test load, any anchors failing the test should be tagged as such.
The failure of an anchor in proof testing is a serious issue and requires the investigation of the cause(s) of failure and an increase in testing rate as follows:
One failure – double the test rate to 1 in 10 and at least 6.
Two failures – double again to 1 in 5 and at least 12
More than 2 failures – test 100% of the job, review the fixing specification and installation method.
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