Flameproof protection relies on robust flameproof enclosures. Constructed with sufficient thickness and mechanical strength, the enclosure can quench internal explosion flames via the width, clearance and surface roughness of joint surfaces, preventing ignition of external hazardous atmospheres. Meanwhile, the enclosure can withstand explosions occurring outside hazardous areas. In summary, flameproof housings deliver both internal explosion resistance and external blast resistance, yet such equipment tends to be bulky.

Intrinsic safety certification limits circuit energy. Even under foreseeable fault conditions, the released energy is insufficient to ignite surrounding explosive substances, achieving inherent safety. Accordingly, intrinsic safety products impose strict requirements on circuit design and operating power, and are generally applied to handheld devices and low-power equipment.

Composite Ex certification adopts two or more protection types when a single mode fails to meet safety requirements. For instance, the antenna part of flameproof devices is usually designed with intrinsic safety structure, forming flameproof & intrinsic safety combined equipment. It should be noted that composite products do not need to fully comply with all criteria of individual protection types, nor do they necessarily possess higher Ex grades. The grade is determined by gas/dust classification, temperature class and equipment protection level.

For more information on intrinsic safety and flameproof Ex certification, please feel free to contact STS.