GLS Tank Manufacturer for Glass Lined Steel Storage Tanks
Created on 09.02
GLS Tank Manufacturer for Glass Lined Steel Storage Tanks
A GLS tank manufacturer makes glass-lined steel storage vessels, commonly called glass-fused-to-steel. The enamel is fused into carbon steel panels at 820 to 930 °C, giving a layer of 0.25 to 0.45 mm rated above 3,450 N/cm², spark tested at 1500 V DC on every panel, and finished at a surface roughness below Ra 0.8 µm. That produces a non-porous interior that will not rust, will not contaminate the stored fluid, and is rated 30 years or more in atmospheric service. Panels about 1.2 m wide bolt together with 8.8-grade bolts and EPDM gaskets, and single tanks are supplied up to 60,000 m³.
Glass-lined steel sits in a narrow technical position between a plastic lined tank and a stainless vessel, and that position is what a buyer is really buying. It is far cheaper than stainless for the same corrosion performance on most water and wastewater duties, and far more durable than a painted or rubber lined interior. When an engineer shortlists a GLS tank manufacturer, the questions are about the fusion process, the panel inspection record, and whether the factory can deliver the diameter the project needs. The rest of the decision is ordinary procurement: documents, lead time, shipping and site assembly.
What glass lining means at the factory
Fused, not applied. The enamel powder is electrostatically applied to a prepared steel panel and fired in the furnace between 820 and 930 °C, so the glass flows into the steel surface rather than resting on it. The finished enamel layer measures 0.25 to 0.45 mm and is rated above 3,450 N/cm² against bending and compression. Because the two materials fuse into one composite, the characteristic failure mode is not delamination of a coating but edge exposure: the cut edge at a flange or a nozzle, and a mechanical chip there. That is why the factory treats the panel edge, numbers every panel, and spark tests each one at 1500 V DC before packing.
The surface finish is the second consequence. A fused enamel panel comes out with a roughness below Ra 0.8 µm, which is the property that makes the same lining acceptable for potable water and food contact grades, and which resists deposit build-up in a wastewater tank. It also covers the full pH range from 1 to 14, so alternating acid and alkali streams do not force a change of lining.
Technical Specification
Parameter | Typical Value / Range | Note |
Firing temperature | 820–930 °C | Enamel fused into the steel panel |
Enamel layer thickness | 0.25–0.45 mm | Rated above 3,450 N/cm² |
Surface roughness | Ra < 0.8 µm | Non-porous, easy clean interior |
Spark test | 1500 V DC | Per panel before shipment |
pH tolerance | 1–14 | Wide and alternating chemistry |
Design life | 30 years or more | Atmospheric storage service |
Panel width and bolts | ~1.2 m panels, 8.8-grade bolts | EPDM gasket flange joints |
Single tank capacity | up to 60,000 m³ | Diameter driven by site logistics |
Certification | NSF/ANSI 61, WRAS, FDA, LFGB, CE (EN 1090), ISO 28765, FM, BSCI | Per project requirement |
Choosing a manufacturer, not a product
The product is standard; the manufacturer is not. A checklist keeps the evaluation honest. Ask for the furnace schedule and the firing temperature range it operates in, the enamel thickness record per panel, the per panel 1500 V DC spark test record with panel numbering, the material test report for the steel, the gasket and bolt certification, the repair procedure for a chipped or pinholed panel, and the dimensional and foundation drawings. Ask how many panels the furnace runs per week and when the booking for your order starts, because lead time is a furnace queue problem, not an order value problem. Ask which product certifications the shop holds and which design references it works to, which for a GLS tank is AWWA D103-09 as the common baseline, AWWA C550 and NFPA where the application requires them, and the ISO 9001 and ISO 45001 quality and safety system for the shop itself.
Then check the two things a spreadsheet will not show. First, whether the press and the furnace handle large panels without distortion, which is the difference between a 20,000 m³ order arriving on time and a rework cycle. Second, whether the packing list reconciles to the assembly drawing, because a missing panel on site is a week of waiting.
Delivery and site scope
A bolted glass-lined tank ships as panels in containers or breakbulk, which matters for an overseas site with a long inland haul. The panels are offloaded against the packing list and checked for transport damage, the gasket is seated in the flange, the bolts are tightened to the recorded torque on the 8.8-grade set, and the shell is assembled ring by ring. The foundation is a ring beam or concrete pad with the permitted settlement stated in the design, because a bolted joint cannot follow a differential settlement. The tank is then tested at atmospheric pressure with water before it takes process fluid, which is the acceptance moment for any weeping joint.
Scope should be written explicitly: the enamelled panels and roof, the bolt and gasket set, the manways and nozzles, the foundation load figures, the assembly or supervision crew, the water test, and the document pack. Where the project needs a vapour tight roof, a floating pan or a gas tight double membrane cover, that is a roof package on top of the same shell and belongs in the same order.
Project Case
Project | Location | Product | Capacity | Scope |
Large diameter potable water storage | Namibia | GLS tank | 44,900 m³ | supply + supervision, large diameter assembly |
Fire water tank, two units | Sichuan, China | GLS tank | 8,930 m³ | supply + supervision, φ19.87 × 14.4 m × 2 |
Municipal effluent tank programme, 10 units | Sichuan, China | GLS tank | 17,420 m³ | supply, multi-tank site |
Center Enamel Engineering Capability
Center Enamel (Shijiazhuang Zhengzhong Technology Co., Ltd) has designed and fabricated bolted storage tanks since 2008. As the first glass-fused-to-steel (GFS) tank manufacturer in China, the company holds close to 200 enamel-related patents, produces roughly 300,000 enamel-coated steel plates a year, has completed more than 30,000 installed projects and supplies its tanks to over 100 countries. The new 150,000 m² production base was added to raise output capacity, and single tanks are supplied up to 60,000 m³. Manufacturing runs under ISO 9001 and ISO 45001, with product certification including NSF/ANSI 61, WRAS, FDA, LFGB, CE (EN 1090), ISO 28765, FM, BSCI and EUROCODE, and design referenced to AWWA D103-09, AWWA C550 and NFPA where the application requires it.
For glass-lined storage this covers the two coat enamel fusion process, the per panel 1500 V DC spark test record, the bolted assembly with gaskets and 8.8-grade bolts, and the roof package for vapour tight or gas tight duty.
Frequently Asked Questions
Q1: What is the difference between GLS and GFS?
A1: The two terms describe the same product family: glass-lined steel, usually written glass-fused-to-steel. The technical description is the same, enamel fused to carbon steel panels at 820 to 930 °C.
Q2: Is a glass-lined tank a pressure vessel?
A2: No. It is atmospheric or low pressure storage. Where a genuine pressure vessel is needed, that is a separate scope supplied to the specification and codes agreed in the contract.
Q3: Why is the spark test at 1500 V DC important?
A3: It finds pinholes and thin spots in the fired enamel on every panel before the tank is assembled. The per panel record is the main factory acceptance document for the lining.
Q4: What is the maximum capacity?
A4: Single tanks are supplied up to 60,000 m³. Beyond that the binding constraint becomes the site route and crane rather than the factory.
Q5: Which documents should the order include?
A5: Material test report, enamel schedule with the firing record, per panel spark test record, thickness record, gasket and bolt certification, dimensional and foundation drawings, torque procedure, repair procedure, and the product certification required.
Q6: Can the tank be extended later?
A6: Yes. Bolted panels allow extra rings or a neighbouring second tank, which is useful when the plant or the site plan changes after commissioning.
Q7: How is the interior kept clean?
A7: By the nature of the surface. A fused enamel interior at Ra below 0.8 µm is non-porous and washes down, with no coating layer to absorb or shed material.
Selecting a GLS tank manufacturer is a process selection as much as a product selection. The fused enamel fired at 820 to 930 °C, the 0.25 to 0.45 mm layer rated above 3,450 N/cm², the Ra below 0.8 µm surface and the 1500 V per panel spark test are the technical facts; the furnace schedule, the document pack and the shipping plan are the commercial facts. Fix both in the specification and the tank becomes a thirty year asset rather than a five year one. Send the capacity, the fluid and the site data to the engineering desk and the selection suggestion and document package will follow.
Talk to an Engineer
Send the storage data for a manufacturer review: required capacity and diameter limits, stored fluid with its pH and temperature, potable or process grade and the certification needed, site coordinates, soil condition, crane capacity, transport route and port, and the project deadline. We will return the tank diameter and height, the enamel system description, the panel count and production sequence, the factory document pack, the shipping plan and the site acceptance procedure. Engineering review first, no obligation.
WhatsApp