When you buy an office chair, the base is also an important part to consider.
Nylon base, steel base, and aluminum base are the common base of the office chair.
Sorted by quality, the aluminum base is the best, and the nylon base is better than the steel base.
The base quality depends on the test. For example, the standard of the BIFMA test is 1136 kg.
Steel base
But in these three bases, the steel base absolutely can not pass the BIFMA test. Because it is hollow inside and welded together by several parts. We can see the welded seam outside easily. Therefore, the manufacturer will add a lid to cover the weld. This construction results in a weak and poor support capacity. Besides, steel base rust easily.
Nylon bases
Nylon bases are made of plastic, but they can pass the BIFMA test. It has a geometric structure inside, the denser it is, the stronger it is. And the nylon base is one mold injection molding, its’ hardness is very strong and much stronger than the steel base. Besides, nylon base is lower cost, so there are many chairs with nylon base on the market.
Aluminum base
The aluminum base also can pass the test. Many people confuse aluminum bases with steel ones. The difference is that the steel has a lid there to cover the weld. The aluminum base is also one mold injection molding, the inside geometric structure makes it very strong.
Summary
While you are looking for a good base office chair if you can not sure if they can pass the test, ask the seller to show you a picture of the inner structure is the best way.
And remember, the denser the geometry, the better it is.