NFPA 704 Ratings From a Safety Data Sheet: Step by Step

Last Updated: 2026-10-19

Answer Capsule: To find NFPA 704 ratings from a Safety Data Sheet, check Section 16 first; it often lists the diamond. Otherwise take flammability from the flash point in Section 9, instability from Section 10, health from Section 11, and special hazards from Sections 5 and 9. Never copy GHS category numbers into the diamond; the scales run in opposite directions.

You searched for an NFPA 704 generator and every result asked you to type in four numbers you do not have. The numbers live in the Safety Data Sheet for each product, and nobody showed you which page. So you guessed, or you copied a rating off a photo of somebody else's sign.

A guessed rating is a real problem at inspection. The fire marshal can ask you to show where each number came from, and "a website" is not an answer. A wrong number on the door also tells the fire crew the wrong thing about what is inside.

This guide walks through the SDS sections in the order that works: 16, then 9, 10, 11 and 5. You will learn what each section gives you, the one mistake that flips a rating backwards, and what to do when two suppliers disagree. Brent Hanke at Print Pro AZ pulls ratings from customer SDS files every week, and this is the method he uses.

Where Is the NFPA 704 Rating on an SDS?

The NFPA 704 rating, when a supplier includes it, is in Section 16, Other Information, at the very end of the Safety Data Sheet. Many suppliers print the four numbers there as "NFPA: Health 1, Flammability 3, Instability 0" or as a small diamond graphic, often beside an HMIS rating.

Every SDS follows the same 16-section format under OSHA's Hazard Communication Standard, 29 CFR 1910.1200. That is good news, because the section numbers below are the same on every sheet, from every supplier, for every chemical.

If Section 16 has the rating, you are mostly done. Write it down, then spot check it against Sections 9 and 10 using the steps below. Suppliers make mistakes, and the facility owner, not the supplier, is responsible for the number on the door.

If Section 16 is blank, build the rating yourself. The criteria are in NFPA 704, and the data you need is spread across four other sections.

How Do You Pull Each Number From the SDS?

You pull each number by matching one SDS section to one quadrant of the diamond. Work in this order and write each result down before moving on.

1. Read Section 16 first. If it lists an NFPA rating, record all four positions: health, flammability, instability, special. Note the SDS revision date.
2. Rate flammability from Section 9. Find the flash point and boiling point. Flash point below 73 F with boiling point below 100 F, or a flammable gas, is a 4. Flash point below 73 F with boiling point at or above 100 F, or flash point 73 F to 100 F, is a 3. Flash point 100 F to 200 F is a 2. Above 200 F is a 1. Will not burn is a 0.
3. Rate instability from Section 10. Look for words like "may detonate," "explosive decomposition," "reacts violently with water," or "unstable at elevated temperature." Readily capable of detonation is a 4. Detonates with a strong initiator or reacts explosively with water is a 3. Violent change at elevated temperature or violent reaction with water is a 2. Stable but can become unstable when heated is a 1. Stable and not water reactive is a 0.
4. Rate health from Section 11. Read the acute toxicity and the skin, eye and inhalation effects. Very short exposure could cause death or major lasting injury is a 4. Short exposure could cause serious temporary or moderate lasting injury is a 3. Intense or continued exposure could cause temporary incapacitation is a 2. Irritation with minor lasting injury is a 1. No hazard beyond ordinary combustible material is a 0.
5. Find special hazards in Sections 5 and 9. Section 5, Fire-Fighting Measures, will say if water is unsuitable or the material is an oxidizer. Section 9 confirms whether it is a gas. Water reactive gets W with a line through it. Oxidizer gets OX. Nitrogen, helium, neon, argon, krypton, xenon and liquefied carbon dioxide get SA.
6. Write the result as H-F-I plus symbol and file the SDS page you used with the rating. That file is your answer when the fire marshal asks.

Example: an acetone SDS shows a flash point near minus 4 F in Section 9, "stable" in Section 10, and skin and eye irritation in Section 11. That is 1-3-0 with no symbol, which matches the table Print Pro AZ prints from. The NFPA 704 diamond explained pillar covers what each of those numbers means at the door.

Why Can't You Copy GHS Categories Into the Diamond?

You cannot copy GHS categories into the diamond because the two scales run in opposite directions. In GHS, Category 1 is the most severe. In NFPA 704, 1 is the least severe. A straight copy flips the hazard upside down.

Callout: Section 2 of the SDS lists GHS hazard classes such as "Flammable Liquid, Category 2" or "Acute Toxicity, Category 3." Those numbers are not NFPA numbers. A Flammable Liquid Category 1 is the most flammable class, but a copied "1" in the red square tells the fire crew it barely burns.

System	Number 1 means	Number 4 means	Where it lives
GHS (Section 2)	Most severe category	Least severe category	Container label and SDS Section 2
NFPA 704	Least severe rating	Most severe rating	Door placard and SDS Section 16

What to do instead: skip Section 2 for the diamond and go to the raw data in Sections 9, 10 and 11. The GHS category tells you a hazard exists. The flash point, the reactivity statement and the toxicity data tell you the NFPA number.

What Do You Do When Suppliers Disagree?

When two suppliers give different NFPA ratings for the same chemical, use the SDS for the exact product and concentration on your shelf, and if both products are in the same room, post the higher number. The facility assigns the rating; NFPA only publishes the criteria.

Disagreement is common. Diesel appears as 0-2-0, 1-2-0 or 2-2-0 depending on the supplier. Methanol and isopropyl alcohol show up as 1-3-0 on some sheets and 2-3-0 on others. Hydrogen peroxide is 1-0-0 at 3 percent and 3-0-1-OX at 30 to 35 percent. Concentration, blend and test data all move the number.

Document the choice. Keep the SDS page, note the revision date, and write one line explaining why you posted the number you posted. If you cannot find a property on the SDS, the NIOSH Pocket Guide lists flash points and exposure data for hundreds of chemicals.

How Do You Turn One SDS Into a Room Placard?

You turn a stack of SDS ratings into one room placard by taking the highest number in each color from any material in the room and adding every special symbol present. That is the worst-case rule, and it is what the placard on the door shows.

Here is a call Print Pro AZ gets every month. A lab manager has rated every bottle from its SDS and has a spreadsheet of thirty rows. What goes on the door? Brent Hanke takes the max of the health column, the max of the flammability column, the max of the instability column, then lists every W, OX and SA. The worksheet method is written out in the NFPA 704 diamond generator post.

Once you have the numbers, a blank diamond and numbers kit lets you post any rating without a custom order, and Print Pro AZ prints fixed ratings in 3 to 24 inch vinyl or aluminum. If you would rather skip the spreadsheet, send the chemical inventory as a PDF, Excel or CSV and Print Pro AZ returns the placard set with the composite rating worked out. For the 50 most common ratings with part numbers, grab the NFPA 704 Diamond Field Guide. Use the download form on this page.

Frequently Asked Questions

Which SDS section has the NFPA rating?

Section 16, Other Information. Suppliers are not required to include it, so it is missing on some sheets. When it is missing, build the rating from Sections 9, 10, 11 and 5 using the steps above.

Is there an official NFPA 704 generator?

No. NFPA publishes the criteria, not a calculator, and the facility owner assigns the rating. Any tool that outputs a diamond is applying the same criteria to data you supply. The Print Pro AZ inventory upload does that work for you from your SDS list.

Can I use the HMIS rating on the SDS as the NFPA rating?

Not as a straight copy. HMIS and NFPA 704 use the same 0 to 4 scale for health and flammability, but HMIS has a PPE bar instead of a special hazards square, and its health bar can carry a chronic asterisk. Check the NFPA numbers against Sections 9, 10 and 11 before posting.

Conclusion

Section 16 gives you the rating when the supplier includes it, and Sections 9, 10, 11 and 5 let you build it when they do not. GHS categories in Section 2 run backwards from NFPA numbers, so never copy them. When suppliers disagree, use the SDS for your exact product and post the higher number for the room.

Getting the numbers right from the SDS the first time means the placard on the door survives inspection and tells the fire crew the truth. Rather hand off the spreadsheet? Send us your chemical inventory and Print Pro AZ will return the full placard set. Questions? Call Brent at (602) 649-5305.

Sources

• OSHA Hazard Communication Standard, 29 CFR 1910.1200
• NFPA 704, Standard System for the Identification of the Hazards of Materials for Emergency Response
• NIOSH Pocket Guide to Chemical Hazards

Brent Hanke | Print Pro AZ | (602) 649-5305 | b.hanke@printproaz.com

Brent Hanke is the founder of Print Pro AZ, supplying NEC-compliant labels to contractors across the country.