Blind flanges for headers, future phases and testing
Data center campuses are built in phases, so headers end in blind flanges that wait for the next data hall. Blind flanges also close test and flushing connections during commissioning.
Order blind flanges in the same class, face and material as the header they close. On stainless clean loops, a 316L blind flange avoids a carbon steel surface in contact with the coolant.
Where blind flanges are used
| Use | Why it matters |
|---|---|
| Header ends for future data halls | Lets the next phase tie in without draining or cutting the live system |
| Flushing and cleaning connections | Temporary pumps and filters connect here during pre-commissioning |
| Hydrostatic test points | Close off sections tested at 1.3 to 1.5 times working pressure |
| Strainer and equipment isolation | Seals a branch while equipment is removed |
Material for clean loops
On the technology cooling system, everything that touches the coolant should be stainless or another approved wetted material. A carbon steel blind flange on a stainless header puts rust-prone steel in the loop. Specify 316L or 304L, pickled and passivated, for TCS and CDU secondary headers.
When a header is left blind for a future phase, record the flange standard, class and face in the as-built documents. The next contractor needs them to order a matching flange.
Frequently asked questions
Can a blind flange be drilled and tapped for a test connection?
Yes. Blind flanges can be supplied with a tapped hole for a vent, drain, gauge or flushing connection. Give the size and thread on the order.
Do blind flanges need the same class as the line?
Yes. A blind flange carries full system pressure on its whole face, so it must match the class and material group of the mating flange.