14-08-2012, 09:52 AM
IMPROVING VENTILATION AND REDUCING HEAT STRESS IN AN ENGINEERING INDUSTRY
IMPROVING VENTILATION.pdf (Size: 37.28 KB / Downloads: 37)
The Problem
A brake linings manufacturing process was generating heat load
into the work environment. This problem was compounded by poor
ventilation in the shop floor. The main reasons for the above
issues were unplanned and periodic increases in plant capacities
by addition of additional equipment and processes. These
additional equipment and processes were generating more heat
as well as affecting the shop floor ventilation. The workers were
exposed to heat above their normal withstanding capacity and
occupational health and productivity were becoming major
concerns for top management. NPC was asked to carry out a
evaluation of ventilation study and recommend improvements.
Problem diagnosis
Major heat radiation into the shop floor were various equipment,
hot products, exhaust heat from ovens and solar heat gain through
the roof. The heat was not able to freely escape into outside air
because of various layout issues such as haphazard location of
equipment / cabins (blocking the air path) as well as other issues
such as inadequate no of windows, ventilators and openings, lack
of insulation etc.
System maintained for shop floor comfort was a mix of various
methods. They were exhaust ventilation with dust extraction
system cum control system, spot air ventilation system, roof
ventilator fans, and ordinary fans.
Study
The shop floors were divided in various manufacturing cells.
Temperature mapping was carried out in various cells. It was
found that shop temperature was 2-3oC above the ambient
temperature. It was found that area near heat sources like ovens
and furnaces were higher than other areas.
Recommendations
More openings through windows and doors were created to
increase natural ventilation. Area for fresh air entry was doubled.
Windows, shutters and other openings had to be kept open
always.
Packing sections was re-oriented to facilitate airflow. Two tier
packing bay, which was blocking the airflow) was removed. This
helped fresh air entry through windows behind packing section.
Thermic fluid pipelines, flanges and all ovens and stacks were
insulated suitable to bring the surface temperature to less than
50oC. Plungers and moulds in gang presses have to be insulated.
Exhaust ventilation fans were provided above all high heat
generating sources like ovens.
Conclusion
Air changes in the shop flow were improved to recommended level
of 15.
The average temperature in the shop floor was bought down by
almost 2oC.
Workers comfort improved contributing to productivity as well as
reduction industrial relation issues.