Limited Access Zone
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Transcript Limited Access Zone
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Subpart Q - Concrete & Masonry
Construction
(1926.700 - 706)
Reinforcing steel - Guarding
701(b)
292
Masonry walls - Bracing
706(b)
23
Masonry construction - Limited access zone
706(a)(1)
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Concrete and Masonry
• Revisions to standard during
the 1990’s
• Standard expands/toughens
protection against wall
collapse
– Revised bracing requirements
– Requires ‘limited access
zones’
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Standard focus
on guarding
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of exposed reinforcing
steel
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Cast-in-Place Concrete
• Cast in place
concrete must be
capable of
supporting, without
failure:
• vertical loads
• lateral loads
• Use ANSI A10.9-1983
• Drawings and plans
• Must be on jobsite
• Must include all
revisions
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Vertical slip-form operation
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Cooling Tower
St. Mary’s West Virginia 1978
• 51 killed
• 170 feet above ground
• Entire form peeled away from newly placed
concrete
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Jump forms atop the St. Mary’s structure
tore loose, pulling work platforms and
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concrete down
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Wreckage 168 feet below the top of the St.
Mary’s tower being picked apart by
investigators looking for clues.
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General Requirements 1926.701
• No construction
loads placed on
concrete structure
unless:
– Employer determines
safe to do so
– Person qualified in
industrial design
– Structure capable
of supporting loads
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Concrete and Masonry
All reinforcing steel on which an
employee may fall must be guarded.
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Concrete and Masonry
• EVERY rebar must be capped
• You are looking at a fine of somewhere
between 45 and 250 dollars per instance
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Concrete
Bucket
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No employee is
ever permitted
to ride concrete
buckets16
Working under loads
• No employee shall
work under concrete
bucket while:
– Bucket is being raised
– Bucket is being lowered
– To the extent practical…
route buckets so no
employees or the fewest
number are exposed
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Concrete Buckets
•If equipped with
hydraulic or pneumatic
gates, must:
•Have safety device
to prevent premature or
accidental dumping.
•Shall be designed to
prevent concrete from
hanging up on top &
sides.
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Concrete pumping systems
• Provided with pipe
supports designed
for 100% overload
• Compressed air
hoses on pumping
systems:
– Positive fail-safe
joint connectors
– Prevent separation
of sections while
pressurized
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Personal Protective Equipment
• If pneumatic hose is
used to pump cement
sand and water
mixture
• Employees must
wear head and face
and eye protection.
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Bulk cement storage safety
• Storage bins and silos:
– Conical or tapered bottoms
• Concrete Mixers:
• Mechanical device to
clear material
• Guardrails on each side
• No employee permitted to
enter unless ejection
system shut down / locked
& tagged out so system
can’t operate.
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Power concrete trowels
Dead-man control:
• Stop automatically
when hand(s) are
released from control
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Bull floats
• If handles could
contact electrical
conductors they
must be of the
non- conductive
type
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•Guarded with semi-circular
enclosure over blade
•Enclosure must provide for
retaining flying blade fragments
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Do You See Any Violations??
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Vertical slip forms
• Rods or pipes on
which jacks climb:
– Designed for that
purpose
– No excessive
distortion during
jacking
– Provided with
scaffolds where
employees are
required to pass
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Removal of formwork
• Forms and shores
(Except those used for
slabs on grade & slip
forms):
– Not removed until
Employer determines
concrete has gained
sufficient strength to
support its weight and
superimposed loads
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CFR 1926.706
Masonry
Construction.
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Concrete and Masonry
• Masonry wall
construction
–Need a
“limited
access zone”
Limited Access Zone (LAZ)
• Shall be established
whenever masonry wall
is being constructed
• Prior to start of wall
construction
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Limited Access Zone (LAZ)
–Height of wall
plus 4’
–Entire length
of wall
–On unscaffold side
–Restricted
entry
Masons
ONLY!
Limited Access Zone
• Shall remain in place
until wall is supported
• If wall is over 8’ tall it
must be braced
• Bracing must remain
until permanent
support structures are
in place
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