c.
Equipment and Protection: Items of equipment for welding shall be
so designed and manufactured, and shall be in such condition as to
enable qualified operators to follow procedures and to attain the
results specified. Protect welders and gas cutters from the light
of the arc and flame by approved goggles, shields, helmets, and
gloves. Replace cover glasses in helmets and shields when they
become sufficiently marred to impair the operator's vision. Take
care to avoid risk of explosion and fire when welding and gas
cutting near explosive or flammable materials. Ventilate welding
and gas cutting operations in accordance with paragraph 29 CFR
1910-SUBPART Q (f) of Title 29 of the Code of Federal Regulations).
d.
Surface Conditions: Do not weld when atmospheric temperature is
less than minus 18 degrees C zero degrees F, when surfaces are
wet, when rain or snow is falling or moisture is condensing on
surfaces to be welded, nor during periods of high wind, unless
welder and work are protected properly. At temperatures between
zero and mins 18 degrees C 32 and zero degrees F heat with a torch
the surface for an area within 80 mm 3 inches of the joint to be
welded to a temperature warm to the hand before welding. Free
surfaces to be welded from loose scale, slag, rust, paint, oil,
and other foreign material. Joint surfaces shall be smooth,
uniform and free from fins, tears, and other defects which might
affect proper welding. Remove slag from flame-cut edges to be
welded by grinding, but temper color need not be removed.
Thoroughly clean each layer of weld metal by wire brushing prior
to inspection or deposition of additional weld metal.
3.1.3.10
Cleaning of Piping
Before installing pipe, thoroughly clean it of sand, mill scale and other
foreign material. After erection but before final connections are made to
apparatus thoroughly clean interior of piping. Flush with water piping
except air and fuel lines, in addition, blow out steam lines with
intermittent high pressure steam blows to promote shedding of internal
scale; blow compressed air and fuel oil lines clean with 552 to 690 kPa
(gage) 80 to 100 psig air dried to a 2 degrees C 35 degree F dew point at
552 kPa (gage) 80 psig. Sterilize potable water piping by means of liquid
chlorine or hypochlorite in accordance with AWWA C651 before placing water
system in service. Take care during fabrication and installation, to keep
piping, valves, fittings and specialties free of loose welding metal chips
of metal or slag, welding rods and other foreign matter. Blowing or
flushing shall in no case be channeled through equipment, pump, control
valve, regulating valve, instrument gage or specialty in the system.
Provide temporary screens, strainers, connections, spool pieces and
bypasses consisting of piping or hoses, pumps and other required equipment
temporarily installed for the purpose of cleaning and flushing piping.
Drain flushing water and test water to the sanitary sewer system.
3.1.3.11
Reduction in Pipe Size
Provide reducing fittings for changes in pipe size; the use of bushings
will not be permitted. In horizontal steam lines, reducing fittings shall
be the eccentric type to maintain the bottom of the lines in the same
plane. In horizontal water mains, reducers shall be set to maintain top of
lines in the same plane.
SECTION 15502N
Page 175
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