"Ordinary Evacuation Entrance"

"Upgrade plan 1: increase the thickness of the protective door, improve the defense of the entrance to the shelter, add a biochemical radiation decontamination room, and upgrade the required survival point 1500"

"Upgrade plan 2: add screen doors, increase partition doors, add maintenance rooms, upgrade the air intakes of the shelter ventilation system, and upgrade the required survival point 1350"

Looking at these two upgrade plans, Chen Xin, who had already obtained enough supplies from the SWAT team, did not consider which plan was more suitable, so he chose to upgrade them all.

For Chen Xin, who can now earn 15 survival points per day, with enough materials to reduce the consumption of survival points to 10%, the consumption caused by using the upgrade method of choosing all two schemes is already within the range he can bear.

It's just that Chen Xin himself didn't expect that an oxygen concentrator made without consuming a few survival points could actually provide him with two survival points every day, which was really beyond Chen Xin's expectations.

However, this is not difficult to understand, after all, in addition to producing oxygen, his upgraded algae oxygen generator also uses the fermentation of biomass to produce biogas, which is used to generate electricity from fuel cells.

It is equivalent to the functions of the three types of equipment, namely oxygen generator, biomass incubator and fuel cell, which has greatly improved Chen Xin's current living conditions, so it is understandable that he can get more survival points.

After choosing to upgrade them all, the door of the shelter was upgraded to the shape he drew on the design drawing according to Chen Xin's idea under the power of the system.

Sturdy and heavy protective doors, a sanitizer room for radiation and biochemical decontamination, a maintenance room for parking cars and equipment, and a defensive corridor with heavy crossbows......

Today's Vault has what a true Doomsday Vault should look like, with a solid and reliable defense.

drove up the car that was originally parked below and parked it in the maintenance room, and Chen Xin also took up the equipment that he might use when he went out.

Hanging the heavy protective clothing in the wardrobe of the maintenance room, and the equipment and materials that need to be carried out are also neatly stacked, Chen Xin looked at everything neatly in front of him, and felt a sense of satisfaction and pride in his heart.

It's like the sense of accomplishment you get when you play Minecraft and finally build a hut where you feel safe and secure.

And unlike the game, this is the real world, this is the real shelter, this is the shelter that can really protect Chen Xin's safety.

By upgrading the entrance to the shelter, Chen Xin also moved the vents and shortwave antennas that originally led to the mountainside to the top of the entrance and placed them in a small bunker made of thick reinforced concrete.

This bunker is not large, just a small space, located above the sanitizer at the entrance to the vault, somewhat similar to a machine-gun bunker in a war game.

This is not a machine gun bunker, although in a sense, as long as Chen Xin mounts a machine gun here, it can indeed be used as a machine gun bunker.

However, the actual function of this small bunker is to protect the short-wave antennas and vents that have been moved here, and it is not true that Chen Xin wants to build a machine gun bunker here.

Although it is likely to be used as a defensive facility in future upgrades, it is now just a bunker for shortwave antennas, and at most a ventilation function.

The exterior of the bunker is covered in dirt from the mountain itself, leaving only a gap about the width of a palm, which cannot be accessed from the outside, and can only be accessed through the passages reserved inside the shelter.

Compared with the shortwave antenna that was originally just covered by a camouflage cloth and placed directly in the open air, the shortwave antenna under the protection of such a small bunker is undoubtedly much safer, and even if it is discovered, it is difficult to destroy this kind of antenna that is placed in a solid bunker.

As for the impact of the bunker on the antenna signal is not impossible, but it is not serious, at least Chen Xin tried it, and he can still receive external signals smoothly and contact others.

The original vents have also been changed after being moved to the inside of the shelter, not only with the addition of a protective cover and grille filter, but also an additional overpressure automatic exhaust valve after entering the interior of the shelter.

This is the ventilation equipment that will be used in civil air defense engineering, the principle is to use the air pressure difference between the inside and outside of the shelter to form a seal, block the invasion of toxic and harmful air from the outside, and can discharge the air inside the shelter to ensure ventilation circulation.

Although it sounds a bit complicated, the structure of this thing is very simple, with it, the shelter does not have to worry about the outside toxic and harmful substances entering the shelter through the ventilation pipe.

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At the entrance of an original shopping mall in the city, Qin Lan and several SWAT team members were holding guns and guarding here.

It was originally a large shopping mall in the city, with an underground supermarket and parking lot, and was planned as a small evacuation shelter before the disaster, which was inhabited by about 5,000 people from the surrounding community.

This small shelter was originally planned to allow some people to escape the apocalypse, and after the disaster, it was used as an underground settlement by connecting it to other shelters through a passage.

However, due to the deterioration of the environment and the temporary inability to supply oxygen generators to small shelters, the city government has no choice but to move people to other medium-sized shelters and temporarily mothballed them.

It is planned to wait until the passage connecting the medium-sized shelter to this area is opened at a later stage, and the oxygen generation equipment is in surplus, and then it will be reactivated.

Qin Lan and they are here to help these people transfer, and in addition to them, there are also staff members of the city government who are responsible for the transfer.

The second batch of oxygen concentrators was shipped in not long ago, but this batch is much less than the previous batch, with only four small biological oxygen concentrators.

Two of them were naturally transported to Binhu Community and Polytechnic Institute, two medium-sized shelters that had not been allocated oxygen generators before, while the remaining two were given to the shelters where the armed police force was located, while the other was distributed to the factory.

It is precisely because of the lack of oxygen generation equipment that the city government has decided to temporarily abandon all small shelters and all medium-sized shelters in the diversion channel for the population.

Although the population of the small shelter is small, only a few thousand, the relocation of a few thousand people is not an easy task, and the staff sent by the city government are already a little overwhelmed, and they need to deal with all kinds of problems.

Qin Lan stood on the firing position on the roof of the armored car with his sniper rifle, his eyes constantly patrolling the crowd, searching for possible dangers.

In this situation, anything can happen, Qin Lan and the others must put an end to any possible criminal behavior and avoid turning into a group incident.