Document ID: OSHA-2008-0034-0015
Agency: osha
Document Type: Supporting & Related Material
Title: 
Posted Date: 2009-08-24T04:00Z

Exhibit No. OSHA-2008-0034-0015

Substantial Differences Between NFPA 51A-2006 and CGA G-1.4-1966:

Additions and Revisions

Section No. in NFPA 51A-2006	

Description of Section

1.4	Adds a new section noting that the standard represents a consensus
of the requirements necessary to protect against the hazards specified
in the standard.

1.5-1.5.2	Adds new sections specifying requirements for equivalent
systems, methods, or devices.

2.1-2.4	Adds new sections listing documents referenced in the standard.

3.1	Adds a new section providing general information regarding the
definition of terms not defined in the standard.

3.2.6-3.2.5	Adds definitions for the following terms:  “Standard,”
“high pressure acetylene,” “low pressure acetylene,” “medium
pressure acetylene,” “approved,” “authority having jurisdiction
(AHJ),” “control areas,” “high hazard contents,” “high
hazard contents, level 2,” “high hazard contents, level 3,”
“high hazard contents, level 4,” “limited-combustible
(material),” “listed,” “mobile acetylene trailer system,”
“normal temperature and pressure (NTP),” “protection levels,”
“protection level 2,” “protection level 3,” “protection level
4,” “shall,” and “should.”

4.2.1.1-4.2.2	Adds new sections specifying requirements for
multiple-occupancy buildings.

4.4.1	Adds a new section specifying requirements for reducing mechanical
ventilation.

4.5-4.5.1.2.2	Adds new sections requiring installation of flammable-gas
detection systems in rooms housing acetylene operations, and specifies
the requirements for using these systems.

4.7.3.1-4.7.3.4	Adds new sections requiring the use of shutoff switches
on various doors, and specifies requirements for using signs to mark the
location of these switches.

5.1.1	Revises CGA G-1.4-1966 by requiring that packages used to store
calcium carbide meet Department of Transportation (U.S. or Canada)
regulations.  Section 3.1.1 of CGA G-1.4-1966 specifies that the
packaging be metal containers that will not rupture, and also are
watertight, during normal handling.

5.2.4.1 and 5.2.4.2	Adds new sections on protecting calcium-carbide
containers from flooding and making contact with the ground.

5.2.6.1	Adds a new section permitting the storage of unopened
calcium-carbide containers that are covered with ice and snow in rooms
or buildings devoted exclusively to the storage of calcium carbide in
drums.

5.2.7 and 5.2.7.1	Adds new sections on constructing buildings used to
store calcium-carbide containers, and specifying the level of protection
required when the quantity of calcium carbide exceeds the maximum
quantity permitted in a control area.

5.3	Adds a new section on storing, and protecting from rain, any area
used to transfer calcium carbide from transport containers to
generator-hopper loading carts/systems.

6.2.3	Revises section 4.1.1 of CGA G-1.4-1966, which specifies that
outdoor installations used to house acetylene generators must protect
the generators from rain and freezing, by adding groundwater to these
conditions.

6.2.7	Adds a new section on preventing backflow in piping used to
transport calcium-carbide residue from acetylene generators.

6.3.2.4	Revises section 4.2.3 of CGA G-1.4-1966 by specifying the option
of having vent pipes terminate in an exhaust hood.  Section 4.2.3 of CGA
G-1.4-1966 allows vent pipes to terminate outside a building, and also
provides specific parameters for locating the terminal point of the
pipes. 

6.3.2.4.1 	Adds a new section specifying requirements for locating
termination points for exhaust ducts serving vent pipes.

6.3.2.4.2	Revises section 4.2.3 of CGA G-1.4-1966 by referencing NFPA 55
for specifications regulating vent pipes that terminate outside a
building.

6.3.2.6	Revises section 4.2.4 of CGA G-1.4-1966 by permitting the use of
multiple pressure-relief devices (instead of only two devices), and
specifying requirements for the cross-sectional area of each
pressure-relief device under such conditions.

6.5.1.1	Revises sections 4.4.1 and 4.4.2 of CGA G-1.4-1966 by specifying
additional requirements for discharging calcium carbide into sewer
lines.

6.5.1,2	Revises section 4.4.3 of CGA G-1.4-1966 by decreasing from 25
feet to 15 feet the minimum distance between an ignition source and the
point at which calcium-carbide residue discharges from a receptacle.

6.5.1.3-6.5.1.5	Adds new sections specifying requirements for (1) using
containment tanks to collect calcium-carbide residue, and (2) the
exhaust-collection systems for these tanks.

7.1.1	Revises sections 5.4.1 of CGA G-1.4-1966 by adding a requirement
that a minimum distance of 25 feet must separate a gasholder and
adjoining property suitable for building or a public way.

8.1.1.1.1	Revises section 6.1.2 of CGA G-1.4-1966 by adding driers to
the list of equipment in high-pressure systems that must have drain
lines piped outdoors, and requiring that these drain lines not be near
combustible material.

8.1.1.1.2	Adds a new section specifying requirements for piping drain
lines to indoor drains from medium-pressure systems and high-pressure
systems reduced to medium pressure or lower.

8.1.1.1.3	Revises section 6.1.3 of CGA G-1.4-1966 to require that vent
lines serving equipment with pressure-release devices comply with
section 6.3.2.  See the descriptions of the differences between section
6.1.3 of CGA G-1.4-1966 and section 6.3.2 of NFPA 51A-12006 above in
this table.

8.1.2.1 and 8.1.2.2	Adds new sections specifying requirements for inlet
and outlet piping control valves for compressors, as well as vent
systems from compressors serving pressure-release valves.

8.2.4.2	Adds a new section specifying requirements for temperature
indicators on final-discharge piping.

8.2.5.1	Adds a new section establishing the gauge pressure for
pressure-relief devices in the final compression stage.

9.1	Adds a new section requiring that the design, fabrication, testing,
and maintenance of piping systems comply with ASME B31.3.

9.1.2	Revises section 7.1.2 of CGA G-1.4-1966, which requires bracing
and supporting acetylene piping “to avoid excessive strains and
vibrations,” by specifying that the bracing and supports must protect
the piping from “coincident internal or external pressure,
temperature, vibration, or other structural loads expected under service
conditions.”

9.2.3, 9.2.3.1, and 9.2.3.2	Requires that gas pipes be tested using
pneumatic testing at 110% of maximum design pressure or hydrostatic
testing instead of pneumatic testing; if hydraulic testing is used, the
test pressure must be at least 150% of design pressure.  Section 7.1.4
of CGA G-1.4-1966 requires that gas pipes be tested at 150% of maximum
operating pressure.

9.3.2	Revises section 7.3.2 of CGA G-1.4-1966 to require that pipes
having a nominal size of one inch (instead of three-quarters inch) be at
least Schedule 80.

9.3.3	Revises section 7.3.3 of CGA G-1.4-1966 to require that pipe
having a nominal size of one and one-quarter inch to one and one-half
inch (instead of one inch to one and one-half inch) be at least Schedule
80.

9.3.6	Adds a new section specifying requirements for pressure gauges
exposed to detonation flames when the gauges serve piping exceeding 15
psig.

9.4	Revises section 7.4.1 of CGA G-1.4-1966 to require that the minimum
burst rating for cylinder-charging leads be 10,000 psi instead of 6,000
psi.

10.1.3	Adds a new section specifying requirements for pressure gauges
exposed to detonation flames when the gauges serve cylinder-charging
manifolds.

10.2.1 and 10.2.3	Adds new sections requiring that storage containers
for solvents meet the construction and installation requirements of NFPA
30, and have secondary containment.

10.3.1 and 10.3.2	Adds new sections specifying (1) maximum pressure
values based on acetylene temperatures, and (2) procedures for operating
valves at the start and completion of charging operations.

10.4	Adds a new section on requirements for cooling cylinders connected
to charging manifolds.

10.5.1 and 10.5.2	Revises section 8.1.6 of CGA G-1.4-1966 requiring
storage of charged cylinders (1) outside the charging room or
out-of-doors according to the requirements of NFPA 55, and (2) at least
15 feet away from charging manifolds that are awaiting transportation in
the charging room.

11.2.1 and 11.2.1.2	Revises section 9.1.3 of CGA G-1.4-1966 by
specifying that (1) buildings or portions of buildings required to meet
Protection Levels 1-4 must have approved automatic sprinkler systems
that comply with NFPA 13 (instead of fire hoses, water sprinkler
systems, or fire extinguishers of the dry-chemical and carbon-dioxide
types), and (2) sprinkler systems provided in areas devoted to the
storage or use of flammable compressed gases must have sprinkler systems
designed to meet the Extra Hazard Group 1 provisions of NFPA 13.

11.2.1.1	Prohibits the use of automatic sprinkler systems in areas used
exclusively for storing or transferring calcium carbide, or for
acetylene generation.  Annex A of this section notes that “[d]ry sand
is typically located in areas where calcium carbide is stored and
used,” and that “[a] 30 gal . . . container with scoop is used to
isolate the calcium carbide from the atmosphere in the event of fire.”
 Section 9.1.2 of CGA G-1.4-1966 prohibits the use of fire hoses,
sprinkler systems, and fire-protection systems using water from the
“immediate areas devoted to calcium carbide handling and storage.” 

11.2.2	Revises section 9.1.4 of CGA G-1.4-1966 by removing the
requirement to locate fire hoses and sprinkler-control valves for
outdoor operation.

11.2.3	Adds a new section requiring an emergency plan that complies with
NFPA 55.

11,2,4	Revises section 9.1.7 of CGA G-1.4-1966 by requiring emergency
alarms that comply with NFPA 55 (instead of audible alarms when plant
buildings are widely separated).

12.2.1	Requires that equipment and piping used in acetylene operations
be electrically continuous and bonded to a grounding electrode as
specified by NFPA 70, while section 9.2.3 of CGA G-1.4-1966 requires
that such equipment and piping be electrically grounded.

12.3	Adds a new section specifying that powered industrial trucks meet
the requirements of NFPA 505.

Substantial Differences Between NFPA 51A-2006 and CGA G-1.4-1966:

CGA G-1.4-1966 Sections Not Available in NFPA 51A-2006

Section No. in CGA

G-1.4-1966	

Description of Section

1.2.2 and 1.2.3	Specifies requirements when plants house operations
involving both acetylene and other compressed gases.

2.1.1	Requires the location of acetylene plants in industrial or
agricultural areas, or equivalent areas.

5.3.1	Requires that equipment have purifies and driers designed to
prevent excessive internal pressure, or, as an alternative, to have
pressure-relief devices.

6.1.1	Requires that the inlet and outlet piping of compressors have
readily accessible shut-off valves for use in an emergency.

8.1.3	Requires cylinder-charging manifolds to have a pressure gage
located downstream of the shut-off valve.

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