When health and safety assessments at Airbus identified a
need to reduce the risk of employee exposure to airborne
chromate (paint) dust generated during fettling operations
the company took prompt action and installed several Local
Exhaust Ventilation systems

Responding to concerns over skin
contamination and inhalation of
chromate dust particles, a multifunctional
Hawker team was set up to
oversee all aspects of the development of a
clean air solution and, following tenders,
appointed clean air and containment
specialist Hosokawa Micron.

Rae Carroll, project engineer at Airbus,
says: “Hosokawa Micron engineers worked
closely with our team refining and modifying
the system specifications to ensure we
achieved the optimum solution. These
discussions became the catalyst for
improvement in our operations which
resulted in a very successful installation,
which is of interest throughout other areas of
the Airbus business.”
The installation included two downflow
booths, one fixed fettling booth, three mobile
fettling trolleys and ancillary systems, all
designed, manufactured and installed by
Hosokawa Micron and which have eliminated
the need for Hawker engineers to wear PPE.

Parts manufacturing/assembly
The downflow booths are designed to offer
high levels of operator protection and
product containment when generating dust
during fettling, drilling and deburring of
large sections of fuselage or other items not
suited to the fixed fettling booth. Each booth
is built over and around the fettling jig giving
full workable access to the panel or unit to be
trimmed or fettled during assembly. The
booths offer a working area of 3m safe
working depth and 5m internal width and
incorporate overhead lighting. A uniform,
non-turbulent, horizontal laminar airflow is
generated behind the operator and flows
across the working area into the rear
perforated distribution plate, taking airborne
dust particles away from the operator’s
breathing zone. The exhaust air is HEPA
filtered before being returned to the booth.

Tests show that chromate OELs are now
well below UK legal limits with workers
undertaking large scale fettling activities no
longer needing to wear face masks.

Parts fettling
Large scale parts fettling is now undertaken
within the 2m wide fixed fettling booth. The
booth with a slotted rear extract plenum is
designed with a horizontal airflow of approx
2.2m3/s that takes dust particles away from
the operator’s breathing zone. Dust particles
are extracted to an external filter unit with
compressed air pulse jet cleaning system.

Dust collected by the filter cartridge is
collected in an external sealed bin for easy
removal and disposal. The system is fitted
with pressure drop monitors and alarm
indicators to further safeguard the operators
from potential exposure to increased levels of
airborne particulates.

The fettling booth has been ergonomically
designed for ease of use and includes overhead
lighting and integral compressed air sockets
that enable air-driven tools to be operated in
the booth with short lengths of airline. The
fully ATEX-compliant system also includes
vacuum extraction for removal of debris.

A transportable solution designed to
reduce operator exposure to potentially
harmful fettling dust, polishing dust and
swarf created in production of painted and
non-painted metal parts or panels, the
booths create a safe working environment
for operators undertaking polishing, drilling
or filing activities where airborne particles
are generated.

The three ‘plug and play’ back-draft
extracted booths incorporate a two stage
filtration system comprising replaceable
panel filter and HEPA filters to H13 grade
standard. HEPA filtered air is discharged into
the factory working area. Constantly
monitored by differential alarm pressure
gauges across the filter, the operator has
visual indication when a filter is laden with
dust and therefore may require cleaning or
replacing. A high performance extraction fan
ensures a reliable air flow through the booth,
even when the filter cells are dirty,
maintaining a safe working environment for
operators.

Complete with lighting and an integrated
Type H vacuum cleaner for the safe removal
of swarf or larger filings the wheeled
Hosokawa Micron fettling trolleys are easily
transported around the workshop.

The LEV project team and workshop
personnel are pleased with the installation
which has lead to a substantial reduction in
the risk posed by chromate dust.