Why a mixed inventory needs a designated-quantity ratio
A small workshop may hold several solvents and fuels, each below its individual designated quantity.
Under Korean rules, dangerous goods stored or handled at the same location must be evaluated by adding each quantity divided by its own designated quantity.
Adding litres alone, or checking each category separately, misses this combined ratio.
This Korea-specific 2026 calculator checks confirmed Class 4 flammable liquids against the national 1× threshold and an existing permit ratio.
It compares current simultaneous stock, planned receipts, planned dispatches and the peak during those movements.
Mixed inventory means a ledger containing several products; it does not mean the products may physically be mixed or stored together.
Supported scope and required confirmations
What is calculated
Enter up to 5 confirmed aggregation locations and 20 inventory rows in total.
The shared calculation converts each item to litres, computes location ratios and identifies current, final and peak quantities.
It shows differences to the national and permit thresholds, item equivalents and unresolved evidence separately for each location.
One held location does not erase another confirmed location’s results.
What needs separate verification
Classes 1, 2, 3, 5 and 6 are outside this interface.
Product names, CAS numbers and partial SDS entries cannot automatically establish legal classification, water solubility, mixture properties or packaging exceptions.
The calculator does not determine compatibility, ventilation, fire protection, safety distances or facility suitability.
Keep unsupported or unknown goods as an unresolved row instead of removing them to obtain a favorable result.
Different rooms or warehouse names do not necessarily create separate legal locations.
Confirm the actual same-location boundary and completeness of the inventory with the safety manager or fire authority.
Do not divide one location into several names to lower its ratio.
Conversely, this tool does not combine distinct locations into one site-wide legal ratio.
Class 4 designated quantities in litres
Enforcement Decree Article 3 refers to the designated-quantity column in Annex 1.
These values were checked against the decree effective July 1, 2026; all Class 4 quantities below are in litres.
Water-soluble and water-insoluble categories have different denominators, so confirm the applicable category rather than inferring it from the product name.
Korean Class 4 legal categories and designated quantities in litres| Legal category and solubility | Designated quantity (L) |
|---|
| Special flammable materials | 50 |
| Petroleum Class I · water-insoluble | 200 |
| Petroleum Class I · water-soluble | 400 |
| Alcohols | 400 |
| Petroleum Class II · water-insoluble | 1,000 |
| Petroleum Class II · water-soluble | 2,000 |
| Petroleum Class III · water-insoluble | 2,000 |
| Petroleum Class III · water-soluble | 4,000 |
| Petroleum Class IV | 6,000 |
| Animal and vegetable oils | 10,000 |
Annex 1 itself was amended April 30, 2024; that date is distinct from the effective date of the whole decree.
Its notes address multiple hazardous properties, product/packaging exclusions and testing used to determine a category.
A line in an SDS does not settle every mixture or exception.
Use an already confirmed legal category and keep the supporting evidence in the row notes.
Understand the inputs and unknown values
Current stock, receipts and dispatches
Current stock means the actual simultaneous maximum stock at the review point.
Combining individual product maxima from unrelated dates creates a hypothetical inventory instead of a consistent snapshot.
Receipts and dispatches describe one movement batch being reviewed, not monthly turnover.
Review multiple interleaved deliveries and dispatches in separate time steps.
Units and confirmed density
Use the same unit for all three quantities within one row.
For goods purchased by mass, select kg and enter that product’s verified density in kg/L.
Do not assume water density or reuse the density of an unrelated product.
A litre entry needs no density conversion; quantities across incompatible units are never added into a meaningless total.
Unknown does not mean zero
A blank number means missing evidence.
Enter 0 explicitly when a quantity is confirmed absent.
An unclassified item, even a zero-quantity row, is not silently treated as a zero ratio: its location total is held pending classification.
If only the permit evidence is missing, a confirmed national-threshold comparison can remain available while permit comparison is held.
Quantity limits are 0–1,000,000,000, density is positive and at most 100 kg/L, and a confirmed permit ratio is positive and at most 1,000,000×, all with up to six decimal places.
These are software input limits, not statutory limits.
Ratio formula and exact threshold comparisons
Volume V (L) = mass m (kg) / density ρ (kg/L)
Item ratio r = V / designated quantity D
Same-location ratio R = Σ(V / D)
Current R0 = Σ(current volume / D)
Final Rf = Σ((current + receipts − dispatches) / D)
Dangerous Substances Safety Control Act Article 5(5) treats a same-location sum of 1 or greater as reaching the designated quantity.
Exactly 1× is already at the threshold.
For water-insoluble Petroleum Class I, 199.999999 L is below 1×, whereas 200 L is exactly 1×.
The engine compares six-decimal inputs with exact rational arithmetic; it does not classify a result from its rounded display.
For a product with confirmed density 0.8 kg/L, 160 kg / 0.8 kg/L = 200 L.
If it is confirmed as water-insoluble Petroleum Class I, dividing by its 200 L designated quantity gives exactly 1×.
Without verified density or classification, this conclusion must remain held.
Step-by-step pre-order check
- Use the permit and site plan to establish the same-location boundary and check that all stock is included.
Select the confirmation only after checking the actual evidence.
- Collect the SDS and classification evidence for each product, including solubility and mixture/packaging treatment.
Leave an unresolved row unconfirmed.
- Enter simultaneous current stock, planned receipts and dispatches in a consistent unit.
For kg entries, record verified density and its evidence.
- Confirm whether receipts or dispatches happen first.
Unknown order produces only a conservative upper bound.
- Enter the verified permit ratio and calculate.
Read current, final and peak ratios alongside the national threshold, permit status and held evidence.
- Save the inventory/checklist TXT for review with the safety manager and fire authority before ordering.
Editing any input clears the prior result; calculate again before saving.
Worked example: final stock hides a temporary excess
Suppose one location holds 80 L of water-insoluble Petroleum Class I and 400 L of water-insoluble Petroleum Class II.
It receives 60 L of the first product before dispatching 200 L of the second; the confirmed permit ratio is 1×.
Although each item remains below its own designated quantity, the combined result is:
Current, receipts-first peak and final designated-quantity ratios| Review point | Petroleum I ratio | Petroleum II ratio | Location total |
|---|
| Current | 80/200 = 0.4 | 400/1,000 = 0.4 | 0.8 |
| After receipt · peak | 140/200 = 0.7 | 400/1,000 = 0.4 | 1.1 |
| After dispatch · final | 140/200 = 0.7 | 200/1,000 = 0.2 | 0.9 |
The final ratio is 0.9×, but the receipts-first peak is 1.1×.
That reaches the national threshold and exceeds the 1× permit by 0.1×.
If dispatch is actually completed first, the peak becomes the greater of the current and final totals: 0.9×.
Changing the schedule selection alone does not establish that real storage or handling is compliant.
How movement order changes the peak
Receipts first
The peak includes current stock plus the entire receipt batch before dispatch.
Future dispatches are not deducted in advance.
A dispatch greater than current stock plus receipts would produce negative final stock and holds the location.
Dispatch first
Every item’s dispatch must fit within its current stock.
The peak is max(current location ratio, final location ratio).
The calculation compares complete snapshots; it does not add maxima for individual items taken at different moments.
Unconfirmed order
Current stock plus receipts is displayed as a conservative upper bound.
National and permit comparisons and equivalent differences remain held so the bound cannot be mistaken for a confirmed peak or clearance.
Check dispatch evidence and delivery timing, select the verified order and calculate again.
Permit comparison and different change procedures
The national 1× threshold and the ratio in an existing permit are separate comparisons.
Equality with a permit is not an excess, but leaves no ratio difference.
Even within the total ratio, individually permitted categories and quantities, facility conditions and technical standards need separate confirmation.
Selecting “No permit document” does not determine that permission is unnecessary.
Act Article 6(1) and Article 6(2)
Review Article 6(1) permission when changing regulated matters concerning a facility’s location, structure or equipment.
Without those facility changes, Article 6(2) addresses changes to stored or handled categories, quantities or designated-quantity ratios, with notification by one day before the intended change.
An ordinary stock movement is not automatically labeled a structural-change permit.
Confirm the required scope and actual filing with the competent authority.
Article 6(3) has specific exceptions for residential heating and certain agricultural, livestock or fisheries heating/drying facilities.
This calculator does not investigate the facility’s use or exception conditions and does not decide applicability.
Agricultural use alone does not automatically exempt all inventory in an ordinary warehouse.
An item equivalent is not an order allowance
The signed difference is threshold ratio minus peak ratio.
A positive number is the difference before reaching the threshold; a negative number represents excess.
Multiply that difference by one item’s designated quantity to express it in litres, holding all other items fixed.
For kg rows, multiply again by verified density to express the equivalent in kg.
At a 1.1× peak and 1× permit, the difference is −0.1×.
This is equivalent to −20 L of water-insoluble Petroleum Class I or −100 L of water-insoluble Petroleum Class II.
These are separate alternatives, not quantities to adjust simultaneously.
At a 0.9× peak, another 20 L of the first product reaches exactly 1×; that is not an allowance for remaining below the national threshold.
If current stock already exceeds a threshold, reducing future receipts alone may not remove the existing excess.
Use equivalent differences to understand the arithmetic, then review which actual quantities and time points can be changed with the safety manager.
Practical uses and common errors
- Painting and repair workshops: enter solvents and fuels under their confirmed legal categories while keeping them within the same-location aggregate.
Similar product names do not prove identical solubility or classification.
- Bulk orders: compare peak ratios before increasing an order for a discount.
Tomorrow’s planned dispatch does not reduce stock received today.
- Warehouse rental or relocation: verify the new location boundary, permit and item-specific limits.
A permit ratio from the old location cannot simply be transferred.
- Inventory evidence: multiple rows for one category are allowed, but do not count the same physical stock twice.
Keep product evidence and a consistent review point for the next reviewer.
Below 1× does not remove every duty.
Act Article 4 leaves technical standards for storage and handling below the designated quantity to metropolitan/provincial ordinances.
This page does not determine local small-quantity reporting thresholds; check the ordinance and fire authority for the actual location.
Frequently asked questions
Is each item being below its own designated quantity sufficient?
No.
Article 5(5) adds the ratios for two or more dangerous goods at the same location.
Small individual quantities may still reach a total of 1×.
Is exactly 1× below the national threshold?
No.
The legal comparison is 1 or greater.
Threshold status uses exact inputs even when a rounded display appears identical on either side of the boundary.
Can I enter kilograms as the same number of litres?
No.
Divide mass by the product’s verified density in kg/L.
Without density evidence, leave the conversion held rather than assuming an equal value.
Can I deduct planned dispatch immediately?
Only a confirmed dispatch-first schedule supports that sequence.
Receipts-first plans include the temporary peak before dispatch.
Unknown order produces an upper bound with comparisons held.
May I omit an unclassified product?
Do not omit it from a complete inventory check.
Keep an unresolved row, hold its location total and confirm the legal category, solubility and mixture treatment.
Does being within the permit ratio allow a new category?
The total ratio alone cannot decide this.
Check permitted categories, individual quantity limits, facility conditions and any category-change notification.
Does below 1× mean no local notification?
No.
National aggregation and local ordinance duties are different.
This calculator does not decide local small-quantity notification requirements.
Are agricultural heating or drying facilities always treated the same?
Article 6(3) contains specific facility exceptions that require individual verification.
This calculator checks general inventory arithmetic and does not establish exception eligibility or permit duties.
Official sources and rule dates
Verified on November 5, 2026 (2026-11-05) using the National Law Information OPEN API.
The evidence covers Act MST 259933, Articles 4, 5 and 6, and Enforcement Decree MST 287381, Annex 1.
Distinguish the Act effective August 7, 2025 (2025-08-07), the Decree effective July 1, 2026 (2026-07-01), and Annex 1 amended April 30, 2024 (2024-04-30).
The current Enforcement Rule MST 287841 was also checked; designated quantities here come from the Decree Annex.
Where a guidance page has older classification wording, verify the current statutory annex first.
Recheck subsequent amendments, actual product classification and density, permit conditions and local ordinances at the time of use.
Save an evidence-backed inventory checklist
Enter confirmed goods and movement plans above to compare current, final and peak ratios.
The downloadable TXT retains inputs, held reasons, permit comparisons, item equivalents and official sources.
Use it with the safety manager and competent fire authority to confirm same-location scope and permission/notification procedures before finalizing an order.