Vietnam's Circular 34/2026/TT-BXD, issued by the Ministry of Construction on 25 June 2026 and effective from 1 July 2026, establishes the current legal framework for classifying construction works into five grades: Special, Grade I, Grade II, Grade III, and Grade IV. For fire safety engineers and project owners operating in the energy, high-rise, aviation, or urban transport sectors, understanding where a project sits in this classification system is not merely a procedural formality — it determines the jurisdiction of the fire authority's design review, the professional certification level required of the design team, and whether BIM and specialised safety assessments are mandatory.
1. The Three-Annex Classification Framework
Circular 34/2026/TT-BXD determines the grade of a construction work through two parallel annexes, with the higher result prevailing:
- Annex I (Tables 1.1–1.5) — Grade by functional importance and operational capacity (output, throughput, passenger volume, etc.)
- Annex II (Table 2) — Grade by structural scale (building height, floor count, gross floor area, basement depth, tank volume, tank height, etc.)
- Annex III — 16 worked examples illustrating how to apply and combine Annex I and Annex II results in practice
The grade of a standalone structure equals the highest grade obtained from any applicable criterion in Annex I or Annex II. For a complex of works or an integrated process line, the grade of the complex follows the grade of the principal structure with the highest individual grade.
2. Sector 1 — Thermal Power Plants
Classification criterion: rated capacity of a single generating unit (MW), not the total installed capacity of the plant. A plant with four 300 MW coal units is a Grade I facility per unit, not Special Grade, even though its combined output is 1,200 MW.
| Sub-type | Special | Grade I | Grade II | Grade III |
|---|---|---|---|---|
| Coal-fired thermal power | ≥ 600 MW | 300 – <600 MW | 50 – <300 MW | < 50 MW |
| Gas-fired thermal power (CCGT / OCGT) | ≥ 750 MW | 450 – <750 MW | 50 – <450 MW | < 50 MW |
Per Section 1.2.5.2, nuclear power plants are classified as Special Grade regardless of installed capacity. This is an absolute designation — no threshold applies.
3. Sector 2 — LNG, LPG & Petroleum Storage
This sector applies Annex I (capacity-based, Sections 1.2.4.3–1.2.4.6) and Annex II (structure-based, Section 2.4) concurrently. The governing grade is always the higher of the two results.
3.1 Annex I — Operational Capacity Thresholds
| Facility type | Criterion | Special | Grade I | Grade II | Grade III |
|---|---|---|---|---|---|
| LNG / LPG storage facilities & bottling plants | Total storage capacity (× 1,000 m³) | > 100 | 5 – 100 | < 5 | — |
| Petroleum & oil product storage depots | Total storage capacity (× 1,000 m³) | > 100 | 5 – 100 | 0.21 – <5 | < 0.21 |
| Gas processing plants | Total throughput capacity (million m³/day) | ≥ 10 | < 10 | — | — |
3.2 Annex II — Structural Scale Thresholds (Tank / Silo)
| Structural criterion | Grade I | Grade II | Grade III | Grade IV |
|---|---|---|---|---|
| Storage volume of tank / silo (× 1,000 m³) | > 15 | 5 – 15 | 1 – <5 | < 1 |
| Height of tank / silo structure (m) | ≥ 75 | >28 – <75 | 6 – 28 | < 6 |
For tanks containing hazardous chemicals or toxic substances, the Annex II result is upgraded by one grade (minimum Grade II; Special Grade is not applicable for this upgrade mechanism).
An LNG import terminal must be classified under both Annex I (storage volume per Section 1.2.4.6) and Annex II (tank height per Section 2.4). The terminal takes the higher of the two grades. In practice, large cryogenic LNG tanks (typically 80–180 m tall, 160,000–200,000 m³) will almost always reach Special Grade or Grade I under both annexes simultaneously. Under Decree 87/2018/NĐ-CP, LNG (liquefied natural gas) and LPG (liquefied petroleum gas) are both sub-categories of "liquefied gas" for classification purposes.
4. Sector 3 — High-Rise Buildings & Building Structures
All building types are classified under Annex II, Section 2.1.1. Four criteria are assessed simultaneously; the highest resulting grade governs.
| Criterion | Special | Grade I | Grade II | Grade III | Grade IV |
|---|---|---|---|---|---|
| Fire-protection height (m) | > H* | >75 to H* | >28 to 75 | >6 to 28 | ≤ 6 |
| Number of above-ground storeys | > 50 | 25 – 50 | 8 – 24 | 2 – 7 | 1 |
| Gross floor area (× 1,000 m²) | — | > 30 | >10 to 30 | 1 – 10 | < 1 |
| Basement depth (m) / No. of basement levels | — | >18 m / ≥5 levels | 6–18 m / 2–4 levels | <6 m / 1 level | — |
The Special Grade height threshold H* is not a single number — it depends on occupancy type as defined in QCVN 06:2022/BXD:
H* = 150 m — Applies to buildings of occupancy groups F1.2, F1.3, F4.2, F4.3 (apartment buildings, dormitories, office buildings, administrative buildings) and mixed-use buildings as defined in Section 1.1.3 of QCVN 06:2022.
H* = 200 m — Applies to all other building types (hotels, hospitals, commercial/retail towers, etc.).
Note: "Fire-protection height" (chiều cao PCCC) is measured in accordance with QCVN 06:2022, and may differ from architectural height above grade.
5. Sector 4 — Airports & Civil Aviation
Civil aviation infrastructure is classified under Annex I, Section 1.4.6. Most aviation facilities are graded at either Special or Grade I — there are no Grade II–IV designations for the main asset types.
| Facility | Classification criterion | Special | Grade I |
|---|---|---|---|
| Passenger terminal building (main terminal) | Annual passenger throughput (million pax/year) | ≥ 10 Mpax/yr | < 10 Mpax/yr |
| Runway (CHC), taxiways, apron | ICAO aerodrome reference code | ≥ Code 4E | < Code 4E |
| Area Control Centre / En-route ATC facility | Fixed (any size) | — | Grade I (all) |
| Aircraft hangars | Fixed (any size) | — | Grade I (all) |
| Airport Control Tower — international airport | Fixed by airport status | — | Grade I |
| Airport Control Tower — domestic airport | Fixed by airport status | — | Grade II |
The ICAO aerodrome reference code (e.g. 4E, 4F) is a two-element code combining runway length category (1–4) and aircraft wingspan category (A–F). Code 4E accommodates aircraft with wingspans up to 65 m — in practice this covers most narrowbody and widebody commercial aircraft including the B737, A320, B777, and A330. Code 4F covers the A380 and B747-8. All current and planned international airports in Vietnam (Noi Bai, Tan Son Nhat, Da Nang, Long Thanh) operate at Code 4E or above, placing their runways and taxiways at Special Grade.
6. Sector 5 — Urban Mass Transit (Metro & Light Rail)
Urban rail classification under Section 1.4.2.1 of Annex I is determined solely by the alignment type of the line — not by ridership, line length, or rolling stock capacity.
| Transit system type | Reference | Grade |
|---|---|---|
| Underground metro (any section running in tunnel) | Section 1.4.2.1(a) | Special (all sizes) |
| At-grade light rail · elevated rail · monorail · steel-wheel tram | Section 1.4.2.1(b) | Grade I (all sizes) |
The key distinction is alignment, not speed or capacity: any metro line with even one underground section is classified as Special Grade for the entirety of the underground alignment. At-grade and elevated sections of the same metro line are classified separately as Grade I under Section 1.4.2.1(b). Intercity and regional railways (not classified as urban mass transit) are graded separately under Sections 1.4.2.2–1.4.2.3 based on design operating speed.
7. Why Building Grade Matters for Fire Safety
The building grade assigned under Circular 34/2026/TT-BXD is a foundational input in the Vietnamese construction and fire safety regulatory system. Its practical consequences include:
| Regulatory function | How building grade applies |
|---|---|
| Fire authority design review jurisdiction | The Ministry of Public Security (MPS) reviews fire safety designs for high-grade projects; provincial fire police review lower-grade projects. The exact split is governed by the fire safety law and subsidiary legislation, using the building grade as the key criterion. |
| Professional certification of design team | Higher-grade projects require fire safety design engineers with correspondingly higher-grade professional practice certificates (chứng chỉ hành nghề). Grade misidentification can render the entire design dossier invalid. |
| BIM and digital deliverables | Government roadmaps (Decision 258/QĐ-TTg and related instruments) link mandatory BIM adoption timelines to project grade. Special and Grade I projects in certain categories are already subject to BIM requirements. |
| Third-party professional liability insurance | Projects with significant community safety impact — generally Special and Grade I — require professional indemnity insurance for the design and supervision team. |
| Periodic safety assessment | High-grade structures are subject to mandatory periodic structural and fire safety assessments throughout their operational life. |
Frequently Asked Questions
A mixed-use tower has 45 above-ground storeys, a gross floor area of 95,000 m², and four basement levels reaching 16 m below grade. What is its building grade?
Assess each criterion independently: (1) 45 storeys → Grade I; (2) 95,000 m² GFA → Grade I (above 30,000 m²); (3) four basement levels at 16 m depth → Grade II (depth 6–18 m, 2–4 levels). The height criterion also needs to be checked against H*. The highest result across all criteria governs — in this case, Grade I on two independent criteria. Height must still be verified against H* (150 m for F-type occupancies, 200 m for others) to confirm whether Special Grade applies.
Our LNG terminal has two full-containment cryogenic tanks, each 85 m tall and holding 160,000 m³. What grade applies?
Assess under both Annex I and Annex II. Under Annex I (Section 1.2.4.6): total storage capacity = 320,000 m³ = 320 × 1,000 m³, which exceeds 100 × 1,000 m³ → Special Grade. Under Annex II (Section 2.4): tank height = 85 m ≥ 75 m → Grade I. The governing grade is the higher of the two results: Special Grade.
Does the building grade under Circular 34/2026 directly determine which fire authority reviews the fire safety design?
The building grade is a key input, but the precise delineation of fire authority jurisdiction (Ministry of Public Security vs. provincial fire police) is governed by the fire safety law and its implementing decrees, which reference project scale and grade as primary criteria. Circular 34/2026/TT-BXD itself defines the classification methodology; the competent fire authority determination follows from that grade in accordance with the fire safety legislation. Project teams should verify the current jurisdiction boundary in the applicable decree before submitting the fire safety design dossier.
Circular 34/2026 replaced Circular 06/2021 — what changed for existing permitted projects?
Key technical changes in Circular 34/2026 include: revised GFA thresholds for building grade (Annex II, Table 2 — the floor area breakpoints were corrected); addition of petroleum storage depots as an explicitly graded facility type (Section 1.2.4.5); clarification of the passenger terminal grade boundary at 10 million passengers per year; and addition of tank height as a parallel structural criterion alongside tank volume. Projects that received building permits or fire safety design approval under Circular 06/2021 retain their original classification for that permit cycle. The new circular applies to projects first submitted for approval on or after 1 July 2026.
Need to determine the correct grade for your project?
VIETSAFE E&C assists project owners and design teams in correctly applying Circular 34/2026/TT-BXD — including multi-criteria assessment, Annex III worked examples, and preparation of the grade justification dossier for submission to the fire authority.
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