Is it still necessary to add a surge protector to circuits that use safety barriers?

A safety barrier cannot replace a surge protector； Surge protectors are not necessary. Surge protectors are only necessary in areas with frequent lightning strikes where the overall lightning protection measures in the installation area are inadequate. 　

If analog control, in my opinion, requires a distributor along with properly wired cables. It’s fine now.

Safety barriers and surge protectors serve different purposes; one cannot replace the other. Between the surge protector on the control room side, the safety barrier, and the field instruments.

It is necessary to install surge protectors in the circuit; safety barriers can limit power

The two serve different purposes: one is for explosion protection and the other for lightning protection; they cannot replace each other.

There is a chemical industry standard that clearly specifies which meteorological areas require surge protection, and which areas are suitable for it (it is merely a recommendation).

What are the standards? Could you post them for me to see?

Indeed, as mentioned above, it depends on the region whether this feature is included or not; it seems that some small manufacturers remove the surge protection mechanism in order to save costs, or their poor designs don’t take this into account at all.

The lightning protection design for instruments is a very complex matter that cannot be explained in just a few words. There used to be a standard recommending the installation of surge protectors south of 26 degrees north latitude. However, the current lightning protection design standards do not specify under what circumstances such design is required; we generally use the average annual number of thunderstorm days as a key reference to determine whether it is a region with frequent thunderstorms or one with few thunderstorms. Generally, if the average number of thunderstorm days per year is greater than 21, it may be advisable to install surge protectors, but this is not mandatory. The decision should be based on the actual lightning activity in the area, the actual usage conditions, as well as the situation of other factories in the vicinity. Careful consideration is needed before deciding whether to install surge protectors, as this involves additional investment, more potential failure points, and higher maintenance costs. Typically, this decision should be made in consultation with the property owner, whose opinion is crucial since they are the ones who will use and maintain the system. Conversely, it’s not the case that surge protectors are unnecessary in areas with few thunderstorms; for example, the western regions of China experience few thunderstorms, but this does not mean they are immune to lightning strikes. Likewise, areas with many thunderstorms are not necessarily affected by them either. I once heard that a petrochemical plant in Xinjiang was severely affected by lightning strikes in one particular year; there were several lightning strikes in that year, and the impact of those strikes was very severe. So it’s hard to say; it needs to be discussed. In fact, all of the above can be summarized in one sentence: it’s a matter of investment. If the property owner is wealthy and willing to spend money, then there is a reason to install surge protectors no matter where it is. For the projects we are currently designing, surge protectors have been installed in the Guangdong region and areas such as the Leizhou Peninsula; no such protectors have been installed in other areas yet. They are all the results of extensive research, discussion, analysis, and comprehensive consideration from various aspects. The above is for reference only. In short, in any region, there is a reason for installing surge protectors, whether or not they are used. However, if surge protectors are to be used, caution is required; one should not act rashly or unilaterally.

Surge protectors prevent lightning damage, while safety barriers prevent explosions.