Sanitary Welding : The Complete Guide [2023]

January 11, 2023December 31, 2020 by Daniel Hayes

The practice followed in the pharmaceuticals and drug industry is known as sanitary welding.

AWS ( American Welding Society) has formed some strict regulations to follow for more hygienic welds, the D18/ D18.1 committee of the AWS created this welding standard.

Strict rules are followed during the welding process as any defect/error may cause serious physical or monetary harm to the industry as well as the consumers.

Well documented weld map and weld logs are issued to the customer/client from the manufacturer. Several tests and checks are done to make sure there is no discontinuity in the welds.

Contents

Why Is Sanitary Welding Important?

Without a doubt, the food and the pharmaceutical industries require hygiene and sanitation as their first priority.

Since the product is consumed by tons of people around the globe and any mistake can create a huge problem for the public as well as the industry itself.

Usually, the welds are somewhat rough and sometimes may even have excessive pitting, this results in a portion of the weld joint which is very hard to clean. Soil and other impurities get trapped in this area and attract microbial growth. This can become a huge problem if not taken care of in the early stage of the microbes growing.

To avoid the problems mentioned earlier, the practice of sanitary welding is followed.

Materials for Sanitary Welding

Food-grade welding and related industries majorly use stainless steel. However, there are over hundreds of different stainless steel grades.

In these industries, the stainless steel grade 316 is used and standardized. For other types of welding the stainless steel grade 304 is used usually.

Sanitary Welding Procedure

To understand the procedure of sanitary welding, we must first know the process of TIG( Tungsten Inert Gas) Welding or GTAW ( Gas Tungsten arc Welding) and Orbital Welding. These are the only techniques that should be used for sanitary welding.

TIG Welding

TIG uses a non-consumable tungsten electrode along with shielding gas( Argon or Helium). The shielding gas protects the weld from environmental contamination as at high temperature, the weld metal tends to chemically react with gases present in the atmosphere such as oxygen, nitrogen, or hydrogen.

TIG Welding is preferred for sanitary welding because unlike other welding methods, TIG produces a very high-quality weld with little to no post-weld cleaning. Also there is Micro TIG welding so that you can weld upto 0.005.

Orbital Welding

This method utilizes a computer-controlled system for welding, which is comparatively a newer method to TIG Welding and requires minimal human participation.

The system controls the arc current, speed while the orbital welding head goes around the assembly to produce consistent weld profiles. The process is repeated as the head rotates around the assembly resulting in a high-quality weld profile.

This method was created to mitigate the problems caused by using TIG Welding. Since the process is automated, the chances of discontinuity of any form are close to nil, offering a huge advantage over TIG Welding which requires manual work.

Sanitary Welding Standards

As the welding practice followed in the dairy and drug industries, sanitary welding has its code to maintain the product quality. The completed weld profile must not have any form of discontinuity or crevices.

The surface of the weld must be smooth and free of any form of cracks. The welds are also required to be corrosion-resistant and cleanable. The cleaning process should be simplified as much as possible to reduce maintenance costs and increasing durability.

Following the code is very important to make a non-toxic impervious weld which will not cause harm of any form.

After the welding process is completed, the weld is purged with inert gases to remove any hazardous gases released during the process.

Purging is often overlooked in the welding process of a small scale, while it’s a very important part of sanitary welding. The projects are usually huge and involve large amounts of mechanical work by welders.

If you want to read the official published documents, head over to the D18 committee of AWS on their official website.

Sanitary Welding Mistakes

1. Welding Different Types of Metals

This mistake can cause serious damages in the form of corrosion, contamination of food, and sometimes the development of cracks on the surface. The problems originate in the design phase, making sure the materials used are of top quality and are of the same type is the only solution.

2. Welding at Corners

In sanitary welding, it is advised to not weld at inner corners instead it must be radiused. Weld in this practice is usually done on flat surfaces which reduces the chances of mistakes close to nil.

3. Over stressed Surfaces

Stressing on the metal surfaces is usually avoided by welders and in this case, it must be avoided at all costs. We are talking about drugs and the dairy industry here, over stressed surfaces ultimately lead to corrosion, stress cracks, etc.

4. Framework should Be sealed

The finished surface must be smooth and must be sealed and not bolted. The body is regularly cleaned and hence the surface should be sealed in such a way that it is cleanable without much hassle.

Sanitary Welding Certification

As any other welding job out there, the sanitary welding also requires a certification for jobs. Also, the fact that this welding job has even more risks when compared to normal welding jobs makes it more crucial during a job hunt.

All major welding schools provide sanitary welding training and sanitary welding certification. The schools take you through the ins and outs of sanitary welding and make you follow a better hygiene practice for welding. *Covid-19 gets angry*