Ventilation

1
Ventilation
2
Dust hazards created by abrasive blasting

• How respirable dust is formed
• Composition and toxicity
• Review exposure limits in 29 CFR 1910.1000

1a
3
Dust hazards created by abrasive blasting

• Organic abrasives
• Flammable or explosive dust

1b
4
Blast-cleaning enclosures

• Exhaust ventilation
• Baffling air inlets and access openings
• Rate of exhaust

2a
5
Blast-cleaning enclosures

• Before opening
• blast must be turned off
• exhaust system must be run
• Protection for observation windows
• Slit abrasive-resistant baffles

2b
6
Blast-cleaning enclosures

• Doors
• must be flanged and tight when closed
• must be operable from both inside and outside

2c
7
Inspection maintenance of exhaust systems

• Z9.2-1960, and ANSI Z33.1-1961
• Dust leaks must be repaired ASAP
• Static pressure drop at the exhaust ducts

3a
8
Inspection maintenance of exhaust systems

• Installations where the abrasive is recirculated
• Dust collectors

3b
9
Personal Protective Equipment

• Abrasive-blasting respirators must be worn
• inside blast cleaning rooms
• when using silica sand
• when toxic dust exceeds exposure limits
• Dust filter respirators

4a
10
Personal Protective Equipment

• Heavy canvas or leather gloves and aprons
• Safety shoes
• Eye and face protection

4b
11
Air quality for abrasive-blasting respirators

• Free of harmful quantities of dusts, mists, or
  noxious gases
• Meets requirements in 29 CFR 1910.134(i)

5a
12
Operating procedures and general safety

• Dust must not accumulate on the floor or ledges
  outside of an abrasive-blasting enclosure
• Dust spills must be cleaned up promptly
• Keep aisles and walkways clear

6a
13
Grinding, polishing, and buffing operations

• Local exhaust ventilation systems
• Remove dust, dirt, fumes, and gases
• Required when employee exposure exceeds
  permissible exposure limits

7a
14
Grinding, polishing, and buffing operations

• Hood and branch pipe requirements
• Design and placement so particles fall or are
  projected into the hoods
• Operation must not cause particles to be thrown
  into the operators breathing zone
• Follow specified exhaust volumes

8a
15
Grinding, polishing, and buffing operations

• Exhaust system requirements
• Designed and tested in accordance with American
  Standard Fundamentals Governing the Design and
  Operation of Local Exhaust Systems, Z9.2-1960
• All exhaust systems must be provided with
  suitable dust collectors

9a
16
Hood and enclosure design

• Functions to
• Protect the operator from the hazards of bursting
  wheels, and
• Provide a means for the removal of dust and dirt
  generated
• Structural strength

10a
17
Hood and enclosure design

• Adaptable to particular machine
• Exhaust hoods for floor stands, pedestals, and
  bench grinders must be designed in accordance
  with figure G-2 of 1910.94(b)

10b
18
Hood and enclosure design

• Swing-frame grinders must be provided with
  exhaust booths as indicated in figure G-3 of
  1910.94(b)

10c
19
Hood and enclosure design

• Portable grinding operations, whenever the nature
  of the work permits, must be conducted within a
  partial enclosure

10d
20
Hood and enclosure design

• Hoods for polishing and buffing and scratch-brush
  wheels must be constructed to conform as closely
  to figure G-4 of 1910.94(b) as the nature of the
  work will permit

10e
21
Hood and enclosure design

• Cradle grinding and polishing operations must be
  performed within a partial enclosure similar to
  figure G-5 of 1910.94(b)

10f
22
Hood and enclosure design

• Hoods for horizontal single-spindle disc grinders
  must be constructed to conform as closely as
  possible to the hood shown in figure G-6 of
  1910.94(b)

10g
23
Hood and enclosure design

• Horizontal double-spindle disc grinders must have
  a hood encircling the wheels and grinding chamber
  similar to that illustrated in figure G-7 of
  1910.94(b)

10h
24
Hood and enclosure design

• Vertical-spindle disc grinders must be encircled
  with a hood so constructed that
• the heavy dust is drawn off a surface of the
  disc
• the lighter dust exhausted through a continuous
  slot at the top of the hood as shown in figure
  G-1 of 1910.94(b)

10i
25
Hood and enclosure design

• Grinding and polishing belt hoods
• must be constructed as close to the operation as
  possible
• the hood should extend almost to the belt
• one-inch wide openings are provided on either side

10j
26
Operations considered to be spray finishing

• Methods wherein organic or inorganic materials
  are utilized in dispersed form for deposit on
  surfaces to be coated, treated, or cleaned
• May involve either automatic, manual, or
  electrostatic deposition

11a
27
Operations considered to be spray finishing

• Does not include
• metal spraying or metallizing
• dipping
• flow coating
• roller coating
• tumbling
• centrifuging
• spray washing and degreasing systems

11b
28
Location and use of spray booths

• Enclose or confine all operations

12a
29
Location and use of spray booths

• Must be located as provided in sections 201
  through 206 of the Standard for Spray Finishing
  Using Flammable and Combustible Materials, NFPA
  No. 33-1969

12b
30
Location and use of spray booths

• Used to enclose or confine all spray finishing
  operations covered by 29 CFR 1910.94
• Terms
• Spray booth
• Spray room

12c
31
Design and construction of spray booths

• 29 CFR 1910.107(b)(1)-(4) and (6)-(10)
• ANSI Z9.2-1960

13a
32
Design and construction of spray booths

• Lights, motors, electrical equipment, and other
  sources of ignition must conform to the
  requirements of 29 CFR 1910.107(b)(10) and (c)
• In no case must combustible material be used in
  the construction

13b
33
Design and construction of spray booths

• Walkways
• Baffles, distribution plates and dry-type
  overspray collectors
• Wet or water wash spray booths

13c
34
Design and construction of spray booths

• Collecting tanks
• Pump manifolds, risers, and headers

13d
35
Design and construction of spray rooms

• Must be constructed of masonry, concrete, or
  other noncombustible material
• Must have noncombustible fire doors and shutters

13e
36
Design and construction of spray rooms

• Adequate ventilation
• the atmosphere in the breathing zone of the
  operator must be maintained in accordance with
  the requirements of 29 CFR 1910.94(c)(6)(ii)

13f
37
Design and construction of spray rooms

• Spray rooms used for production spray-finishing
  operations must conform to the requirements for
  spray booths

13g
38
Ventilation during spray finishing operations

• Ventilation must be provided in accordance with
  provisions of 29 CFR 1910.107(d)

14a
39
Ventilation during spray finishing operations

• Where a fan plenum is used it must be of
  sufficient strength or rigidity to withstand the
  differential air pressure or other superficially
  imposed loads for which the equipment is designed
  and also to facilitate cleaning - 29 CFR
  1910.94(c)(5)(iii)

14b
40
Ventilation during spray finishing operations

• Inlet ductwork
• Exhaust ductwork

14c
41
Velocity and air flow requirements

• Except where a spray booth has an adequate air
  replacement system, the velocity of air into all
  openings of a spray booth must be not less than
  that specified in Table G-10 of 29 CFR 1910.94(c)
  for the operating conditions specified

15a
42
Velocity and air flow requirements

• Adequate air replacement system
• Total air volume

15b
43
Velocity and air flow requirements

• Respirator is required when the operator is
  downstream from the object being sprayed
• Downdraft booth doors must be closed when spray
  painting

15c
44
Make-up air in spray finishing operations

• Clean fresh air must be supplied to a spray booth
  or room in quantities equal to the volume of air
  exhausted through the spray booth

16a
45
Make-up air in spray finishing operations

• Self-closing doors, dampers, or louvers
• Filtered air supply
• Heating make-up air

16b