243.1 PAS128/ASCE depth classes (plain)

Summarize confidence levels so reviewers grasp uncertainty. Depth class drives whether an HVM bollard line shifts or a crash rated bollard adopts a shallow system (244).

Utility survey outputs come with an accuracy class and a depth class. In plain English: “High” means proven by trial pit or records; “Medium” means detected by GPR/EM with good geometry; “Low” means uncertain, interference likely. Choose more conservative shallow foundation options when classes are low.

For crash-rated projects, depth class affects two things: (a) feasibility of footing depth; (b) the evidence you’ll need later in the Inspection & Test Plan (ITP) to prove you respected clearances. When in doubt, escalate proving digs at limited points instead of guessing.

243.2 Typical minimum clearances

State radial/vertical buffers around pipes/cables. Clearances steer HVM bollard centers and qualify crash rated bollard anchor zones (332).

Set a “no-go” envelope around live services: a radial buffer from the trench wall and a vertical buffer below the socket base. Treat HV power, gas mains, and fiber backbones as “red” risks with larger stand-offs. If uncertainty exists, widen the buffer or upgrade to proof via trial pit. These buffers influence array centers and can force a change of foundation class in 332 Foundation types.

Record the agreed clearances directly on 936 mark-up overlays so site teams and reviewers share one interpretation. Where gradients or groundwater add risk, coordinate with 334 Drainage before finalizing depths.

243.3 Sleeve/duct options

Introduce protective sleeves and diversion ducts (246). Sleeving can save HVM bollard geometry and keep a crash rated bollard socket feasible.

Sleeving and short diversions reduce strike risk and can maintain the intended array rhythm without large re-routes. For signal and low-voltage runs, specify smooth-bore ducts with generous radii and labelled draw pits. For water and gas, coordinate material, appurtenances, and testing with utility owners and log everything in the 917 submission index.

Document sleeve diameters, cover, and separation rules in the IFC drawings and 934 trench details. For automatic systems, reserve cable capacity for safety devices (photo-eyes/loops) and future spares; cross-link with 344 Induction loops and 515 Cables & routing.

243.4 Re-route vs shallow base

Decision hinges on cost, approvals, and risk (422). Reroutes preserve HVM bollard performance; shallow bases keep a crash rated bollard buildable (244).

Where deep sockets clash with utilities, you have two families of solutions: (a) re-route the service; (b) adopt a tested shallow base from the same product family. Re-routes can be slow and permission-heavy but often preserve ideal clear-gap geometry. Shallow bases install faster and avoid diversions but may need wider plan areas or grade beams; confirm equivalence in 422 Depth & utilities choices and 414 Standards equivalency.

Always check the certificate’s as-tested configuration and whether a shallow variant is covered. If not, you need a vendor letter plus engineering justification recorded in your 433 Specification.

243.5 Conflict decision tree

Map detect→verify→decide→approve. A simple tree reduces HVM bollard redesign and documents crash rated bollard justification (444).

Detect: From 241 Utility Search Methods and 242 Underground Detection, capture GPR/EM findings with classes. Verify: Escalate to trial pits for red-zone clashes. Decide: Compare re-route vs shallow base with programme and cost. Approve: Package the decision for reviewers and log into the 444 Evidence & Documentation trail.

Keep the tree in the design report and re-run it after site discoveries. Tie stop-work triggers to discovery of uncharted utilities and document the stop-work trigger in MS/RA.

243.6 Authority approvals

List what drawings/calcs they need (133–134). Approvals unlock HVM bollard excavation and crash rated bollard pours (611–624).

Compile service-owner NOCs, trench details, and protection measures with stamped plans, utility coordinates, and trial-pit photos. For the UAE, align with SIRA Bollards (UAE) where scope touches security approvals, and reference a clear programme float for permits per 717 Authority Submittals and 938 Submission-Pack Guidance.

Downstream, ensure installation sequencing respects permits and hold points in 624 Pouring & vibration and 611 Pre-works setup & permits.

243.7 Mark-up on drawings

Cloud conflicts, add notes, and revision tags (931, 537). Transparent mark-ups protect HVM bollard intent and crash rated bollard dependencies (421).

Use the 936 Mark-Up & Overlay Standards with consistent clouds, leader notes, and descriptive anchors for each clash. Cross-reference drawing keys to the 537 change log and keep a clean “issue for use” trail. Tag all sockets whose depths changed so the 421 rating-critical dependencies remain visible.

243.8 Build risk register

Track likelihood, impact, owner (719). Keeps HVM bollard risks visible and flags crash rated bollard foundation contingencies (335).

Create a utilities risk line for each clash with likelihood/impact scoring, controls (e.g., hand-dig zones), and an accountable owner. Add programme impacts and mitigation (night works, permit float). Link back to 719 Nonconformance & Defects for escalation and to 335 Underground Utilities for technical context.

243.9 Example clash log

ID, location, utility, action, status. A tight log prevents HVM bollard delays and anchors crash rated bollard decisions for 938.

Minimum columns: Clash ID · Chainage/offset · Utility owner/type · Survey ref with PAS 128/ASCE class · Decision (re-route | sleeve | shallow base) · Permit status · Owner · Target date · Evidence link. Store it under your Submission-Pack Guidance (938) so reviewers can trace decisions quickly.

On discovery of uncharted services, log a stop-work trigger, call out a hold point, and update the 612 Setting-Out coordinates to reflect any line shifts before pours.

243 Utilities conflicts & depth classes for Crash-Rated Bollards — FAQ