# What a data center actually needs on site

Checked 2026-11-05. Live: https://datacenterskilledtrades.com/briefs/on-site/

A data center is a building designed for continuous power and heat rejection. On the ground that means a power path (utility feed → switchgear/UPS/generators → PDUs), cooling (CRAH/chillers + liquid/hydronic loops), fiber trunks and splices, a concrete-and-steel shell, and the people and trucks that install and keep those systems running.

Electricians, HVAC techs, pipefitters, cabling crews and building trades do that work. Where no named filing gives a headcount, megawatt figure or water volume, we leave the number out.

## Audiences
- Everyday readers: walk the physical campus: power in, heat out, fiber out, shell, crews and deliveries.
- Local gov / HOAs: demand plain physical scope, employer by work package, dated utility/water filings; refuse invented headcounts and MW.
- Contractors / GCs: staff scope by system; put gating cert next to each crew; keep national load/water on their kits.

## What’s physically on site
### Power path
Electricity arrives from the utility, then goes through switchgear, UPS and (usually) generators before it reaches the racks through PDUs.
- What’s there: Utility feed → substation / service → switchgear → UPS → generators & ATS → PDUs → racks
- Who gets the call: Electrician (licensed) inside the building; lineworker on the utility feed
- Credential: State electrical license; NFPA 70E-aligned training (employer-common)
- Tools: NFPA 70E checklist (/checklists/nfpa-70e/), cert checker (/cert-checker/#role-electrician), who gets hired (/briefs/who-gets-hired/#row-power)

### Cooling: air and liquid
Heat leaves the building through computer-room air handlers (CRAH), chillers, and: increasingly: liquid/hydronic loops that move heat with water or glycol.
- What’s there: CRAH/CRAC + chillers (refrigerant) · chilled-water / glycol / CDU facility loops (hydronic) · heat rejection (towers, dry coolers, or chillers)
- Who gets the call: HVAC/R for refrigerant CRAH/chillers; pipefitter for facility water/glycol/CDU loops; OEM tech often on the CDU itself
- Credential: EPA Section 608 (federal law) when a refrigerant circuit is opened; OEM training per vendor for CDUs
- Tools: EPA 608 guide (/guides/epa-608/), liquid cooling guide (/guides/liquid-cooling/), failure map (/facility-systems/#liquid-cooling)

### Fiber & structured cabling
Glass fiber trunks, splices and patch panels are the physical plant that carries data between halls and out of the campus. That plant is low-voltage / BICSI work: not an IT ticket.
- What’s there: Outside-plant / campus trunks → entrance → trays → patch panels → splices → rack links
- Who gets the call: Low-voltage / limited-energy installer (often on an electrician’s crew)
- Credential: BICSI INSTF / TECH (employer-common); Oregon LEA or Washington 06 where those states license the work
- Tools: BICSI INSTF guide (/guides/bicsi-instf/), fiber cert checker (/cert-checker/#role-fiber), fiber failure path (/facility-systems/#fiber)

### Shell: concrete & steel
Before any rack is live, the building itself has to stand: foundations, slabs, structural steel, walls, roofs, firestopping. That is ordinary commercial construction: general contractors and building trades, not a software release.
- What’s there: Earthwork → foundations / slabs → structural steel → envelope → interiors / firestopping / pathways for the systems above
- Who gets the call: General contractor + concrete, ironworkers/steel, carpenters, and the specialty trades that cut openings and firestop for power/cooling/fiber pathways
- Credential: Standard commercial construction licenses and GC scope; we print no crane counts, pour yards, or crew sizes
- Tools: who gets hired (/briefs/who-gets-hired/), who’s building (/#whos-building)

### People & trucks
A live or under-construction campus is a jobsite: GCs coordinating trades, trade contractors on power/cooling/fiber/shell, deliveries of gear and materials, utility crews on the feed. Who shows up is a “who gets the call” question: not a headcount we invent.
- What’s there: GC + trade contractors · equipment / material deliveries · utility / lineworker crews on the feed · commissioning and ops handoff
- Who gets the call: See who-gets-hired matrix: electrician, HVAC/R, pipefitter, low-voltage/BICSI, lineworker: plus GC and building trades on the shell
- Credential: Official OEWS tables for NAICS 518200 suppress construction employment and do not publish electrician/HVAC/lineworker/pipefitter rows: most trades work for contractors coded elsewhere
- Tools: who gets hired (/briefs/who-gets-hired/), jobs vs power (/briefs/jobs-vs-power/), roles (/roles/)

## Demand in proposals
- A plain scope of what is physically on site: power path, cooling design (air + liquid/heat rejection), fiber plant, and building shell: in the proposer’s own words.
- Which employer does each piece of work (owner ops, GC, trade contractor, utility): not a vague “data center jobs” line.
- Which trade and which gating credential for power (license + NFPA 70E training), refrigerant (EPA 608), loops (pipefitter / OEM), and fiber (BICSI; OR LEA / WA 06 where licensed).
- Dated utility capacity / interconnection language for any load or rate claim: see grid-load brief.
- Dated water figure (consumed vs withdrawn, avg vs peak, cooling design) for any water claim: see water brief.
- Honest “unknown” where a headcount, campus MW, gallons, or rate is not in a named filing. Do not accept a national total divided by a campus count.

## Don't pad into bids / presentations
- Invented crane counts, pour yards, tons of steel, or crew sizes for a “typical” campus.
- Invented FTE-per-MW or campus electrician/HVAC headcounts (OEWS 518200 does not publish them).
- Campus MW, retail rate impacts, or water gallons not in a named utility/permit/engineering filing.
- “Fiber is IT” or “liquid cooling = zero water / zero trades” claims.
- Any number that is not in the owner’s engineering basis or a dated primary filing: write “per owner’s basis: pending” and leave it out.

## Citable facts
- On-site power path (facility, not IT): Utility feed → switchgear / UPS / generators → PDUs (2026-11-05). Electrician inside; lineworker on the utility feed. NFPA 70E training is employer-common; state electrical license is law.. Source: DataCenterSkilledTrades facility-systems + who-gets-hired (authority file) https://datacenterskilledtrades.com/facility-systems/ (retrieved 2026-11-05) Note: No campus MW, no invented electrician headcount.
- On-site cooling path: CRAH/chillers (refrigerant) + liquid/hydronic loops (2026-11-05). HVAC/R opens refrigerant (EPA 608 = federal law). Pipefitter owns facility water/glycol/CDU loops. OEM often services the CDU.. Source: DataCenterSkilledTrades liquid-cooling guide + EPA 608 guide https://datacenterskilledtrades.com/guides/liquid-cooling/ (retrieved 2026-11-05) Note: No invented gallons, PUE, or tonnage.
- On-site fiber / structured cabling: Trunks, patch panels, splices: low-voltage / BICSI, not IT (2026-11-05). BICSI INSTF is the optical-fiber install credential employers ask for; OR LEA / WA 06 where those states license limited-energy work.. Source: DataCenterSkilledTrades BICSI INSTF guide + cert checker https://datacenterskilledtrades.com/guides/bicsi-instf/ (retrieved 2026-11-05) Note: No invented fiber strand counts or splice counts.
- Building shell: Concrete foundations/slabs + structural steel + envelope (2026-11-05). Ordinary commercial construction under a GC. Pathways, trays and firestopping serve the power/cooling/fiber systems above.. Source: DataCenterSkilledTrades on-site brief (plain construction fact; no primary count source claimed) https://datacenterskilledtrades.com/briefs/on-site/#shell (retrieved 2026-11-05) Note: We deliberately omit crane counts, pour yards, tonnage of steel, and crew sizes: none verified for a generic campus.
- Official trade headcount inside NAICS 518200 (data hosting): Not published (construction employment suppressed; electrician/HVAC/lineworker/pipefitter rows absent) (OEWS May 2025 (released 2026-05-15)). BLS OEWS May 2025 industry-specific estimates. Most facility trades work for contractors or utilities coded outside 518200.. Source: BLS OEWS May 2025 oesm25in4 NAICS 518200 https://www.bls.gov/oes/special-requests/oesm25in4.zip (retrieved 2026-11-05) Note: Do not invent FTE-per-MW or campus trade headcounts from this gap.
- Credential note: refrigerant cooling: EPA Section 608 Technician Certification (2026-11-05). Federal law (40 CFR Part 82 Subpart F) for anyone who maintains, services, repairs or disposes of equipment that could release covered refrigerants: CRAH/chillers included. EPA states credentials do not expire.. Source: U.S. EPA Section 608 technician certification https://www.epa.gov/section608/section-608-technician-certification (retrieved 2026-11-05) Note: Required by law. Fee not published by EPA (testing orgs set their own).
- Credential note: critical power safety: NFPA 70E-aligned electrical-safety training (employer-common) (2026-11-05). Consensus standard employers use for electrical safety around UPS, switchgear and energized work. Not a license or a single national exam.. Source: DataCenterSkilledTrades NFPA 70E checklist (issuer proof footnotes) https://datacenterskilledtrades.com/checklists/nfpa-70e/ (retrieved 2026-11-05) Note: Employer-common: not a substitute for a state electrical license.
- Credential note: optical fiber install: BICSI Installer 2 Optical Fiber (INSTF); TECH broader (2026-11-05). When fiber fails, low-voltage/BICSI pathway gets the call, not IT. INSTF validates install, terminate, splice, test, troubleshoot.. Source: DataCenterSkilledTrades BICSI INSTF guide https://datacenterskilledtrades.com/guides/bicsi-instf/ (retrieved 2026-11-05) Note: Employer-common. OR LEA / WA 06 are state law where they apply. Fees handbook-only (left null).

## FAQ

**What does a data center actually need on site?**
Power that almost never fails, cooling that keeps the machines from overheating, fiber that carries the data, a building shell of concrete and steel, and the people and trucks that install and keep those systems running. That work is trades and construction, not a software release.

**Who shows up on a data-center build site?**
A general contractor coordinating the job; trade contractors for electrical, HVAC/R, pipefitting, low-voltage/fiber and building trades; deliveries of gear and materials; and utility or lineworker crews on the feed. DataCenterSkilledTrades does not invent headcounts: official OEWS tables for the hosting industry suppress construction employment and omit electrician/HVAC/lineworker/pipefitter rows.

**Is fiber an IT job?**
No. Trunks, splices and patch panels are low-voltage / BICSI work. IT owns servers, configs and routing. When fiber fails, the low-voltage pathway gets the call: INSTF is the optical-fiber install credential employers ask for. See /guides/bicsi-instf/.

**Pipefitter or HVAC for cooling?**
Both, on different sides. HVAC/R owns refrigerant CRAH/chillers (EPA 608 when the circuit is opened). Pipefitters own facility water, glycol and CDU primary loops. The CDU unit itself is often OEM-serviced. See /guides/liquid-cooling/.

**How many electricians or HVAC techs does a campus employ?**
Official data does not say. In BLS OEWS May 2025 for NAICS 518200, construction employment is suppressed and electrician, HVAC/R, lineworker and pipefitter rows are not published. Most trades work for contractors coded elsewhere. We do not invent FTE-per-MW. See /briefs/who-gets-hired/ and /briefs/jobs-vs-power/.

**What should local governments and HOAs demand in a proposal?**
A plain scope of what is physically on site (power path, cooling design, fiber plant, shell), which trades and which employer (owner vs GC vs trade contractor vs utility), dated utility capacity/interconnection and water filings where claimed, and an honest “unknown” where numbers are not in a named filing. Do not accept invented headcounts, campus MW, gallons, or rates. Checklists: /briefs/grid-load/, /briefs/water/.

**What should contractors and GCs not invent in scope?**
Do not invent crane counts, pour yards, FTE-per-MW, campus trade headcounts, gallons, or retail rate impacts. Staff the bid by system: power, refrigerant, loops, fiber, shell: and put the gating cert next to each crew. Leave unsourced numbers out.

**How should I cite this?**
Cite 'DataCenterSkilledTrades, What a data center needs on site (2026-11-05), https://datacenterskilledtrades.com/briefs/on-site/' and the Dataset 'Data-center on-site systems: power, cooling, fiber, shell, people: verified system/cert facts and honesty rules'.

Who's building (dated context): /#whos-building, /facility-systems/#whos-building

Related: /facility-systems/, /briefs/who-gets-hired/, /briefs/grid-load/, /briefs/water/, /briefs/jobs-vs-power/, /briefs/jobs-outlook/, /briefs/local-gov-questions/, /guides/liquid-cooling/, /guides/epa-608/, /checklists/nfpa-70e/, /guides/bicsi-instf/, /cert-checker/, /roles/