Flood engineering
Built above the flood line. Then we raised it.
Both of our buildings stand on land that flooded in 2012. That is not an accident. The Meadowlands are where the region’s fiber and power cross on their way into Manhattan, and we would rather engineer for water than pretend it is somewhere else.
01 The number
One number we design to
Every critical system in both buildings sits at or above a single elevation, our design flood elevation: 18.5 feet above the North American Vertical Datum of 1988 (NAVD 88). We use one figure for both sites so that nobody has to remember which building has which rule.
For comparison, the base flood elevation on the effective flood map, the level of the flood with a 1% chance of happening in any year, is 10.0 feet at SEC1 and 11.0 feet at NWK1. The state’s rules for buildings in flood hazard areas ask for one foot above it. We ask for 7.5 feet above the higher of the two.
02 Derivation
How we got to 18.5 feet
| Component | ft |
|---|---|
| Base flood elevation, higher of our two sites (NWK1) | 11.0 |
| Sea-level rise to 2100, high scenario in the state’s current projections | +5.1 |
| Allowance for surge and wave uncertainty in a shallow, enclosed estuary | +1.4 |
| Freeboard | +1.0 |
| Design flood elevation | 18.5 |
Until 2022 the sea-level line in that table read 2.0 feet, the then-current projection for 2070, and our design flood elevation was 15.0 feet at SEC1 and 17.0 feet at NWK1. When the projections moved we chose the later date and the higher scenario, because a data center built today will still have customers in it long after 2070. The full reasoning is in our flood design basis, CGD-DB-004 revision 3, which customers can ask for. The program that followed is the Raise.
03 Where things are
What sits where
| System | SEC1 | NWK1 |
|---|---|---|
| Switchgear and UPS | 21.0 ft (electrical gallery) | 20.6 ft (electrical rooms) |
| Generators | 20.0 ft (plinths) | 20.6 ft (plinths) |
| Fuel tanks | Below grade, double-walled, anchored against flotation; fill and vent points at 20.0 ft | Belly tanks under each set, on the plinths |
| Standard data halls | 16.8 ft, behind a barrier to 19.5 ft | 19.4 ft |
| Dry Floor | 34.2 ft | 36.1 ft |
| Meet-me rooms | 16.8 ft (MMR-A) and 34.2 ft (MMR-B) | 19.4 ft (MMR-N) |
| Fiber entrance vaults | Below grade, sealed; conduits sealed to 19.5 ft | Below grade, sealed; conduits sealed to 19.5 ft |
| Fire pumps | 20.0 ft | 20.6 ft |
| Storm pumps | Four, 2,400 gal/min each, on generator power | Two, 1,800 gal/min each, at the dock |
| Staff supplies | Bunk room for 12, five days of food and water, at 34.2 ft | Bunk room for 10, five days of food and water, at 36.1 ft |
Two items in that table are below the line on purpose. Fuel is safest underground, so at SEC1 the tanks are below grade and sealed, and everything you need to fill, vent or draw from them is above it. Fiber has to come in from the street somewhere; the vaults are sealed, the conduits are sealed to the top of the barrier, and the cables rise inside the building to rooms that are dry.
04 Assumptions
What we assume will fail
A flood is not one event. It is a week in which several ordinary things stop working at once. Our plans assume all of the following, together:
- Utility power fails for up to five days. We hold 72 hours of fuel at full design load on each site and have two supply contracts with priority clauses; in 2012 the region’s fuel trucks could not reach many buildings for three days.
- Roads close. Sedgebank Road floods at a high spring tide. Staff on the shift when a warning is issued stay; the bunk rooms are on the Dry Floor.
- The streets’ fiber vaults flood. Some networks will go down outside our buildings. That is why we keep two sites on different routes, and why we tell customers to buy from more than one network.
- The forecast is wrong. Gates and the dock barrier go up on a warning, not a certainty. We have deployed them nine times since 2021 and needed them twice.
05 Testing
Testing it
Storm pumps are run monthly. The SEC1 barrier is fully deployed once a year and partly deployed whenever a high tide or a warning calls for it; the NWK1 dock barrier is deployed every quarter. The full record is on the barrier page, and every deployment that affects access is posted on the status page.