According to Yonhap News Agency, at 4:55 pm local time on the 15th, a carbon monoxide poisoning accident occurred at the construction site of an apartment building in Paju City, Gyeonggi Province, South Korea, causing three serious injuries and seven minor injuries.
According to reports, after the incident, the fire department dispatched 38 rescue workers and 17 equipment to the scene for the first time to rescue the injured and send them to the hospital for treatment. Two seriously injured patients who fell into coma have now regained consciousness and are basically out of danger.
According to preliminary analysis, the cause of the accident may be carbon monoxide poisoning caused by workers using charcoal stoves for heating during underground concrete maintenance operations.
Concrete curing is the artificial creation of certain humidity and temperature conditions, so that the newly poured concrete can be normal or accelerate its hardening and strength growth.
In winter, the temperature is low, and the concrete needs to be cured after construction. For the concrete curing in low temperature environment in winter, the coal-fired steam curing is generally used in the north, and the honeycomb briquette furnace heat storage curing and hot water curing are generally used in the south.
1. Coal-fired steam curing: In the process of generating steam, this method produces a large amount of harmful gases (carbon dioxide, sulfur dioxide, nitrogen oxides) and PM2. 5。 Therefore, when the carbon furnace is used for concrete curing, the shed should be equipped with sufficient fire fighting equipment, and ventilation measures should be taken before personnel enter the shed to prevent carbon monoxide poisoning.
For some large precast beam yards, it is necessary to invest more funds to build a steam boiler room and arrange steam delivery pipes along all the pedestals of the beam yard. The long delivery distance of the steam delivery pipes also directly leads to large heat loss along the way, and the process of steam curing requires 24 hours of uninterrupted shifts.
2, heat storage maintenance of that honeycomb briquette stove; In this way, a plurality of small honeycomb briquette stoves are generally placed in the covered concrete, and the heat generated by the combustion of the coal stoves is used for heat storage and heat preservation, which has no effect on moisture retention, and more carbon monoxide gas is generated in the combustion process, and the carbon monoxide will aggravate the carbonization of the concrete after contacting with the surface of the concrete. At the same time, the existence of carbon monoxide in the maintenance shed has great potential safety hazards to the construction personnel entering the interior. The shed shall be equipped with sufficient fire fighting equipment, and ventilation measures shall be taken before personnel enter the shed to prevent carbon monoxide poisoning.
III. Hot water curing in winter; this method generally uses electric heating to boil water to a certain temperature and then spray it on the concrete surface, which has a certain effect of heat preservation and moisture preservation. However, with the loss of water and the rapid loss of heat, some areas on the concrete surface may freeze when the temperature drops due to water storage and untimely heating.
4, there is also an electric heating steam curing method; In this way, steam is generated by electric heating, which is pollution-free. However, in the construction process, it is still necessary to manually control the start and stop, and to judge whether to supply steam by manually measuring the temperature and humidity of curing. Therefore, the curing quality is closely related to the responsibility of the operator, especially the temperature measurement at night is difficult to implement, so there are greater limitations.
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