Warning to the public!
The unscrupulous have found many ways to greedily fool the consumer with substandard product.
Undersized or underweight rebar
Commonly known as the “mura” as opposed to “standard” rebar, the undersized rebar is simply a thinner lighter, and therefore weaker rebar than what is purchased.
The Philippine National Standard for rebar allows for a +/- 6% variance in the nominal weight of the rebar. Structural engineering of buildings and other construction are therefore designed with the lower variance considered.
Unscrupulous manufacturers will deliberate roll a rebar with -10% or more variance!
These lightweight products are unsafe, and will not perform to the design specification and standard.
When caught, the common excuse is to claim it is a smaller specification. For example, an undersized 12mm if caught will be declared as an “oversized” 10mm. Or more commonly, an undersized 10mm rebar if caught will be declared as an oversized 8mm bar. Consumers should not be fooled by this, and the Philippine Standard was crafted anticipating this excuse. Hence an oversized bar greater than +6% is also not permitted.
Uncertified imports or unmarked rebar
Rebar is a mandatory standard product as declared by the Bureau of Product Standards because its quality has an impact on public safety. Imported rebar must go through a stringent process of securing an Import Commodity Clearance (ICC) which includes certifying its bar mark.
Imported rebar that do not have an approved bar mark did not go through testing. The reason why an effort was made to avoid of testing is simple: It will without a doubt fail the test.
Some local manufacturers also deliberately roll rebar without bar marks. This is also to avoid tracing substandard rebar product to the origin.
Fake rebar made from wire-rod
Rebar is made from billets, as stated in the Philippine National Standard.
Unscrupulous manufacturers used cheaper wire rods and roll them to have features similar to rebar. These are fake rebar.
Wire-rods are used for making wire, and the steel grade has properties for wire and not fit for the strength required by rebar. The minimum yield strength for the lowest grade of rebar is 230 megapascals or 33,000 pounds per square inch of force (to permanently elongate the rebar). Wire-rod that are used to make fake rebar have a yield strength of 170 megapascals or lower, and thus will fail when used for load bearing structures.