TM 5-852-4/AFM 88-19, Chap. 4
copper tubing into which a common thermometer can be
portability or reusability, and access openings for
inserted will give fair results. The temperature of the
equipment and personnel. Winds in excess of 100 mph
concrete surfaces, the air temperature of any protective
are common in some areas. Where drifting snow and
enclosure and the outside air temperature should be
high winds are prevalent, even the smallest openings
taken at least twice daily and recorded. Additional
must be avoided to prevent filling of the enclosed space
readings should be taken whenever the situation
with snow.
Enclosures or shelters may be self-
warrants. The humidity of heated enclosures should also
supporting or extensions to the existing structural
be recorded. The surface temperature of the concrete
framework.
Enclosed scaffolds, suspended from
should be taken in numerous places including edges and
outriggers, provide a convenient and easily moved
corners. Surface temperature of satisfactory accuracy
shelter for workmen and material. Standard sections of
can generally be obtained by placing a thermometer
tubular scaffolding can also be covered to provide an
against the surface under a cover of insulating material
economical shelter, particularly for structures four or five
until it registers a constant temperature.
stories in height. Buildings designed as prefabricated
structural shells that can be erected on prepared
foundations in a matter of hours or at most a few days
6-5. Protection against the environment.
under even the worst outdoor conditions appear to offer
a. General.
While it is true that most
distinct advantages, as interior finishing can thereafter
foundation construction is accomplished in summer in
proceed in comfort, with the aid of temporary heat,
order to provide prepared support so that structures may
without need for any special enclosure; the building shell
be erected without seasonal constraints, it is often
serves as its own protective enclosure.
necessary to extend foundation work into winter
c. Heating and light for winter work.
seasons.
Provisions for protection of construction
(1) In addition to enclosing the work for
against winter conditions should be initiated well before
winter protection, heat must be supplied to protect new
the first heavy frost or snowfall and in far northern
concrete from freezing, thaw out and warm aggregates
locations they should be ready at all times. While
and prevent frost heaving, as well as provide an
weather records can indicate the probable date of first
efficiently comfortable environment for workmen. Like
freezing temperatures and snow, the possibility of a
shelters, heating requirements depend on the scope of
significantly earlier date should be assumed. Adequate
work to be performed. Heaters range from steam
and timely protection of work can often save the expense
boilers, warm air units and electrical space heaters to oil
of removing and replacing damaged material and
or gas-fired salamanders. The most commonly used
equipment. Often enclosures for winter protection can
heaters are oilfired space heaters producing up to
be advantageously employed to protect the work also
800,000 Btu/hr.
from sun, precipitation, dust, heat and wind, and to
(2) While it is desirable to maintain some
provide conditions for maximum worker efficiency.
degree of full-time surveillance on all heating equipment,
b. Barriers against temperature, precipitation
cokeburning equipment should never be left unattended.
and wind.
Adequate ventilation should be provided for all heating
(1) the protection required for winter
units except electrical ones for the health and safety of
construction varies with the construction material, the
workmen and because of fire and other hazards. Some
severity of the weather, and the duration and type of the
heaters (e.g., those using solid fuels) produce sulfurous
work. As noted in the preceding section, uninsulated
acid which produces excessive corrosion.
Carbon
forms with tarpaulins and availability of temporary heat if
dioxide, which is produced by all fuel burning units, can
needed may be adequate for some phases of work;
damage new concrete". Improper combustion such as
others may require insulated forms with supplementary
from clogging of fuel nozzles in oil-fired units, especially
heat. Temporary portable shelters or enclosures may be
types not vented outside the enclosure, can badly
utilized to enclose all or a portion of the work-9,'94'.
contaminate the enclosure space with soot or atomized
Such protection permits the contractor to maintain
but unburned fuel as well as produce carbon monoxide.
schedules irrespective of weather and ensures maximum
Infrared lamps have been used to keep fresh concrete
quality and productivity.
The efficiency of men,
from freezing. The lamps can be easily positioned and
unhampered by extra clothes and the effects of the
when arranged in a reflector in banks of three to five
elements, is often a prime consideration in selecting the
bulbs can protect a considerable area. With any type of
type of enclosure to be used.
warm air or radiant heating system it is especially
(2) Enclosures may consist of light
important that proper moisture and humidity conditions
portable buildings skidded to or erected over the work
be maintained at the surface of the concrete and that the
site, airinflated shelters, or timber or metal framing
concrete not be overheated. Electricity can also be used
covered with transparent plastic films, tarpaulins or
to
canvas, plywood or building board. In addition to cost,
enclosure selection should consider amount of light
desired, effect of wind and snow, heating, ventilation,
6-11
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