These Guidelines provide guidance for checking dimensions,
buoyancy and buoyancy distribution to ensure that each RTD produced
will represent the same in-water performance characteristics as the
original prototype. This validation should be performed after initial
construction and repeated after reassembling the RTD following buoyancy
calibration checks.
2.1 Spot check foam inserts. While it is not necessary
to conduct a full check of all the dimensions of the foam, a spot
check of one out of every five RTDs should be made of a representative
sampling of foam pieces against the dimensions in the appropriate
annex to the Revised recommendation on testing of life-saving
appliances (resolution MSC.81(70)).
The values should be within ± 6 mm.
2.2 The following should be recorded for each
RTD produced:
-
.1 date of construction;
-
.2 serial numbers;
-
.3 total buoyancy of the RTD;
-
.4 buoyancy of the foam inserts, as follows:
-
.1 combined buoyancy of four front panels;
-
.2 combined buoyancy of collar and back panel;
and
-
.3 calculated total buoyancy (sum of four front,
collar and back panels); and
-
.5 measurements made according to these Guidelines.
3
Fabric and webbing measurements
3.1 Place a small mark on the shoulder seam 44.5
mm from the inside edge of the neck seam (see figure 1). This mark
will be the reference point for measuring distances on the front and
back panels. The vertical webbing should be within ± 6.5 mm
of this point.
Figure 1 Establish reference point
on the shoulder seam
3.2
Shoulder loop. Measure the distance
from the reference point to the location where the inside edge of
the yellow webbing first passes under the black shoulder loop (see
figure 2). This distance should be 73 ± 6 mm.
Figure 2 Check distance to
shoulder loop
3.3
Chest strap. Measure the distance
from the reference point to the top of the chest strap (see figure
3). This distance should be 168 ± 6 mm.
3.4 Waist belt. Measure the distance
from the reference point to the top of the waist belt (see figure
3). This distance should be 416 ± 3 mm.
3.5 Front panel length. Measure the
distance from the reference point to the bottom of the foam (see figure
3). This distance should be 489 ± 6 mm.
Figure 3 Check the overall length
of front panel and the location of the closures
3.6
Waist belt. Measure the distance
from the reference point over the shoulder and down the back panel
to the top of the waist belt (see figure 4). This distance should
be 515 ± 6 mm.
3.7 Back panel length. Measure the
distance from the reference point to the bottom of the back panel
(see figure 4). This distance should be 550 ± 6 mm.
Figure 4 Check the overall length
of back panel and location of waist belt
3.8
Collar attachment location. To
check the collar attachment location, hold the RTD by the collar,
keeping the collar level so the RTD hangs freely. Measure from the
top back edge of the foam down to the centre of the neck seam as shown
in figure 5. This distance should be 342 ± 6 mm.
Figure 5 Check the collar
attachment location
3.9
Webbing attachment to collar.
To check the location of the vertical webbing attachment to the collar,
measure the distance from the edge of the foam (at the end opposite
from the zipper) to the front seams of the box-X stitching (see figure
6). This distance should be 111 ± 6 mm.
Figure 6 Check location of
vertical webbing attachment to collar
3.10
Webbing length (chest strap to collar
attachment). To check the length of the vertical webbing from
the top of the chest strap to the attachment at the collar, measure
the inside distance between the box-X stitches located on the chest
strap (front panel) and on the underside of the collar (see figure
7). This distance should be 263 ± 6 mm.
Figure 7 Check length of webbing
from chest strap to collar attachment
3.11
Finished waist belt assembly length.
To check the finished length of the waist belt assembly, measure the
overall length with the buckle unfastened and the adjustments in the
full open position (maximum length). Lay the RTD on a flat surface
and measure the fully extended length of the assembly. For consistency,
measure the distance from where the snap hook fastens in the D-Ring.
This distance should be 1700 ± 12 mm.
3.12
Finished neck size. A suitably
sized cone (such as a traffic cone) should be used to check the finished
neck size. The cone should be rigid, have a slope of 8.5° ±
1.5°, and be tall enough to allow the RTD to fit as shown in figure
8. If a flexible cone (such as a plastic traffic safety cone) is used
it should be filled with rigid foam, concrete, or similar substance
to make it rigid.
3.13 With both chest and waist belt buckles fastened
and the waist belt adjusted to the full open position, place the RTD
on the cone with just enough force so it will fit snug to the cone,
but not forcing it down.
Figure 8 Positioning the
RTD
3.14 Place a mark on both sides of the cone where
the shoulder seam contacts the cone (see figure 9). This mark may
be used to facilitate subsequent validations. Measure the circumference
around the cone at the mark. The circumference should be 395 ±
6 mm.
Figure 9 Check circumference of
finished neck