# Mr. Charles E. Tudor — Hazardous Materials Safety Interpretation

- **operation:** document
- **citation:** 12-0038
- **title:** Mr. Charles E. Tudor — Hazardous Materials Safety Interpretation
- **source type:** guidance
- **agency:** Pipeline and Hazardous Materials Safety Administration
- **status:** guidance
- **official:** true
- **published on:** 2012-05-07
- **effective on:** Not available
- **summary:** 12-0038 concerning 172.101, 173.22, 173.304, 173.306.
- **machine formats:** - **json:** https://regulus.evalyn.ai/document/phmsa-interpretation-12-0038.json
- **markdown:** https://regulus.evalyn.ai/document/phmsa-interpretation-12-0038.md
- **app url:** https://regulus.evalyn.ai/document/phmsa-interpretation-12-0038
- **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretations/2012/120038.pdf
**body:**

<<<PAGE 1>>>

U.S. Department
of Transportation
Pipeline and Hazardous
Materials Safety
Administration
1200 New Jersey Avenue. SE
Washington, D.C. 20590
MAY 0 7 2012
Mr. Charles E. Tudor, CP-P/MH
12419 Entiat River Road
Entiat, W A 98822
Reference No.: 12-0038
Dear Mr. Tudor:
This responds to your January 23, 2012letter requesting clarification of the Hazardous
Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the packaging of nitrous
oxide in non-specification cylinders. In your incoming letter, you describe a scenario in
which your client intends to ship 7.5 grams of nitrous oxide in a 10-ml non-specification
cylinder via air and vessel internationally. These nitrous oxide non-specification cylinders
are to be used in medical devices. Based on this scenario, your questions are paraphrased
and answered as follows:
Ql. Is nitrous oxide permitted to be transported in 10-ml non-specification cylinders for
domestic and international air transport?
Al. The answer is no. The Column 7 entry in the Hazardous Materials Table (HMT;
§ 172.101) for "UN 1070, Nitrous Oxide" lists Special Provision A14. Special
Provision A14 states that nitrous oxide is not authorized to be transported as a
limited quantity in accordance with§ 173.306 when transported by aircraft.
Therefore, nitrous oxide, when transported by air, must comply with the
requirements specified in either§§ 173.304,173.314, or 173.315. Specifically,
§ 173.304(t) provides the authorized specification cylinders permitted, filling
requirements, and outer packaging requirements for the air transport of oxidizers,
including nitrous oxide. Nitrous oxide would only be permitted to be shipped by
aircraft in a non-specification cylinder if the shipment utilized a special permit. It
should be noted that nitrous oxide transported by highway, rail or vessel meeting the
limited quantities for compressed gas requirements specified in § 173.306 may be
transported in non-specification cylinders.
Q2. If nitrous oxide is permitted to be transported in 10-ml non-specification cylinders
for domestic arid international air transport, what filling limits should be used?
A2. As noted above, nitrous oxide is not permitted to be shipped in 10-ml non-
specification cylinders by air unless a special permit is issued providing relief from
the requirements of the HMR. Furthermore, as specified in the table in
§ 173.304a(a)(2), nitrous oxide has a maximum filling density of 68% when
transported in accordance with the HMR. Shipments transported under the

<<<PAGE 2>>>

Q3. A3. Q4. A4. Q5. A5. Q6. A6. Q7. International Civil Aviation Organization's Technical Instructions (ICAO TI) must
comply with the filling limits listed in packing instruction (PI) 200.
Does USG 18 and § 173.304(t) apply to air shipments of nitrous oxide?
The answer is yes. For air shipments of nitrous oxide transported in the United
States, both USG 18 and § 173.304(t) would apply.
Does PHMSA require fire-resistant outer packaging on vessel shipments of
oxidizers, specifically nitrous oxide?
The answer is no. The requirements in§ 173.304(t)(3) requiring a rigid fire-resistant
outer packaging are specific to air shipments of oxidizing gases. There is no
analogous requirement for vessel transport.
Should 10-ml nitrous oxide non-specification cylinders be treated as "articles" and
be packaged in accordance with PI 003 as indicated by the International Maritime
Dangerous Goods (IMDG) code?
In accordance with§ 173.22 and Chapter 2 of the IMDG code, it is the shipper's
responsibility to properly class and describe a hazardous material. This Office does
not perform that function. However, it is the opinion of this Office that, the scenario
you describe, "UN 1 070, Nitrous Oxide" is the most appropriate proper shipping
description. Furthermore, under the IMDG code "UN 1 070, Nitrous Oxide" should
be packaged in accordance with PI 200.
If the 10-ml nitrous oxide non-specification cylinders are to be treated as "articles"
are they required to be packaged in combination packagings that have been UN
performance tested?
As stated in A5, it is the opinion of this Office that in the scenario you describe "UN
1070, Nitrous Oxide" is the most appropriate proper shipping description.
Therefore, for vessel transport under the HMR, the nitrous oxide could be packaged
in accordance with§§ 173.304, 173.306, 173.314, or 173.315. Under the IMDG
code, nitrous oxide should be packaged in accordance with PI 200.
Is there an existing special permit covering the nitrous oxide cartridges described
above?

<<<PAGE 3>>>

A7. PHMSA's Approvals and Permits Division has issued special permits authorizing the
use of non-specification cylinders for the air transport of nitrous oxide under specific
transport conditions and after a technical review of the non-specification cylinder.
Based on the schematic drawing you provided in your incoming letter, it does not
appear as if your non-specification cylinder has been issued a special permit. Under
§ 107.105, you may apply for your own special permit that authorizes air shipment
of nitrous oxide in non-specification cylinders. You may contact our Approvals and
Permits Division at (202) 366-4535 for more information.
I hope this satisfies your inquiry. Please contact us if we can be of further assistance.
Sincerely,
T. Glenn Foster
Chief, Regulatory Review and Reinvention Branch
Standards and Rulemaking Division

<<<PAGE 4>>>

Office of Hazardous Materials Standards, PHMSA
Attn: PHH-1 0
US Department of Transportation, East Building
1200 New Jersey Avenue, SE.
Washington DC 20590-0001
Attn: Charles Betts, Division Director
Greetings:
My specific questions relate to the shipment of nitrous oxide in cartridges, in particular
cartridges that are small non-spec cylinders--the same as commonly used for C02 for a
myriad of consumer applications.
My client wishes to ship 8 ml cartridges internationally as a consumable that is used in a
medical device they are developing. The filling limit is 0.75 as per the table in
ICAOIIATA (higher than the 0.68 permitted in the CFR at 173.304 table of filling limits).
Cartridges of nitrous oxide are in common consumer use as blowing agents for home
dispensers of whipped cream, possibly of foreign origin. My client needs the ability to
ship the cartridges world wide by air and vessel. They desire to package them in
relatively small quantities for distribution to doctors.
Question 1. Can these cartridges containing nitrous oxide be offered for
domestic/international air transport? If so, can they be filled based on the filling limits
table in ICAO and IMDG? Or are they limited to low pressures of aerosols? (See
discussion)
Question 2. Ifthey can ship by air does USG 18 apply (173.304(f)) to these cartridges?
Question 3. Has PHMSA imposed fire resistant outer packaging on vessel shipment of
oxidizers? Or more specifically, for cylinders of nitrous oxide?
Question 4. Are these cartridges to be treated as "articles'' as is indicated by the IMDG
Code use of PI 003 instead of P200?
Question 5. If they are articles in combination packaging, are they required to be UN
performance tested? Note that the IMDG Code PI 003 does not require UN performance
testing. This could result in a miss match for import/export if this were to be used.
Question 6. Is there an existing special permit covering these N20 cartridges?
Page 1 of3

<<<PAGE 5>>>

The IMDG Code entry references PI P003. Column 17 of the Table suggests that this
entry is for mixtures of propane and butane used in camping stoves. This type of
cartridge is low pressure and not what we have here. P003 treats cartridges as "articles",
whereas the CFR and ICAO/IATA is rather silent on this.
None of the modal regulations define "Receptacles, small containing gas (gas
cartridges)". The common everyday C02 cartridge has been around for nearly a hundred
years. Its use for other gases is common (I know they are used for helium in addition to
nitrous oxide.) It is interesting that the regulations do not specifically recognize these
cartridges as a standard package form.
Further investigation turned up an interesting special permit SP-7951 that has been in
existence for a long time. A specific aerosol can with this permit mark is Land-O-Lakes
brand 16 oz., whipped heavy cream by Land-O-Lakes, Inc., distributed by WhiteWave
Foods, Broomfield, CO. and purchased at a Costco. The can lists nitrous oxide as the
propellant. The permit (issued to ConAgra, Inc.) doesn't mention nitrous oxide and lists
authorized shipping names as Compressed gas n.o.s. and Consumer Commodity. The
permit also authorizes shipment by cargo and passenger air without mention of DOT
31 FP outer packaging which would seem inconsistent with provisions of the regulations
not covered by the permit. This permit has nothing to do with cartridges per se. I have
not found a permit that does apply to nitrous oxide cartridges.
I have been reading these regulations for 40 years but never had to deal with these
critters. So, have I missed something or are the regulations a bit vague on this subject?
I look forward to your prompt response.
Charles E. Tudor, CP-P/MH
HM Packaging Compliance Consultant
12419 Entiat River Road
Entiat, W A 98822
Ph.: 509 784 0264
Email: cetudor4143@gmail.com
Attachment (2)
Page 3 of3

<<<PAGE 6>>>

DISCUSSION:
As I read the regulations for Nitrous oxide, UN 1070 a 2.2 gas with a sub risk of 5.1:
"Excepted Quantity" provisions do not apply to air or vessel transport due to sub-risk.
Limited Quantity provisions for UN 1070 in the CFR apply only to surface transport.
(See Special Provision A14 in the Table.) For domestic surface transport it appears that
173.306(a)(1) would permit shipment as Limited Quantity, but the water is muddied by
1733.306(j) which limits pressure in small receptacles to 970 kPa (141psi) and
"containing no HM other than a Division 2.2 gas". Does the sub-risk 5.1 represent
"another HM"?? Nitrous oxide is shipped at much higher pressure requiring 1800 psi
rated cylinders.
173.304(f) specifically addresses nitrous oxide in air shipment and requires spec
cylinders with relief devices and a UN performance tested (PO I, II) fire/heat resistant
overpack (DOT 31 FP). Non-spec cartridges or articles are not discussed.
There is no Limited Quantity provision for UN 1070 in ICAOIIA TA. PI 200 specifically
requires cylinders other than UN marked cylinders to meet the requirements of the
national authority of the State where they are approved and filled. (How does one know
if there are no marks on them?) PI 200 also requires cylinders of nitrous oxide to have
relief devices so if these cartridges are "cylinders" by definition (this is not clear) then
they cannot be shipped under this regulation (unless approved by you-the competent
authority). If they can be considered cylinders then USG 18 requiring the fire resistant
overpack would apparently apply. The only discussion of cartridges specifically in PI 200
is imposing the hot water bath in Section 6.4.4.1. Apparently pressure is not an issue.
There is no Limited Quantity provision in the IMDG Code for UN 1070. P200(1) again
specifically requires pressure relief devices and does not discuss non-refillable cartridges.
Looking further-
Considering the PSN "Receptacles, small, containing gas or Gas cartridges (oxidizing)
without a release devise, not refillable and not exceeding 1 L capacity,) UN203 7:
This description very much describes the shipment. But ....
The CFR again references 173.304/.306 and SP A14-back to square one-are
cartridges limited to 970 kPa or can they be filled to 0.68/0.75 density per the table??
ICAOIIATA references PI 203 and SP A167 (which invokes the 6.4.4 hot water bath). PI
203 addresses aerosols and gas cartridges but appears to limit the max pressure at 55°C
to 1500 kPa (217 psi). This doesn't fit for nitrous oxide.
Page 2 of3

<<<PAGE 7>>>

Component Specification
Document Number: 10072
Nitrous Oxide Cylinder, 8 gram
Revision: D
7.5 GRAMS N20 / 10 ml
FOOD GRADE • CRIMPED CLOSURE
ARTICLE No.
0173
PIERCABLE DIAPHIRAGAI
_/28.7=0.2
MIN Ø2.5
UNPLATED THICKNESS 0.37/0.43
10m 1== 61013
MASS OF GAS
MASSE DE REMPLISSAGE
GASMASSE
(7.5+0.25g
N20
WATER CAPACITY
VOLUME
(VOLUMEN
MIN
10.3ml
MIN
FULLDICHTE
FILLING DENSITY
0.75kg/l
DESITE DE REMFLISSAGE
MAX
MUrDnUCK = INNCNDAUCK DEI
TEST PRESSURE = PRESSURE OF CONTENTS AT
PRESSION DE CONFOLE : PRESSION INTERNE A
65:5°C
0.75 +0.05
WALL THICKNESS
BURST PRESSURE OF CYLINDER
PRESSION D'ECLATEMENT DE LA BOUTEILLE
HEKSIUKUCK DES ZYEINDEHS
50MPa
MIN
65 =0.5
KAPPENANSTECHKRAFT
CAP PIERCING FORCE (Si SPEC VIA.P.001X)
450N
FORCE DE PERCUTION
MAX
ARBEIT EEM CURCKSTECHEN DER KAPPE
CAF FICACING WORK (SE SPC VIA.Г.001 1)
0.75Nm
MAX
TEXT LOCATION
SUAFACE TREATMENT
TRAYAL FOUR LA PERFORATION DU CAPUCHON
OBERFLACHENBEHANDLUNG
IN ACCORDANCE WITH
laquered
pink
TRAITEMENT DE SURFACE
CYLINDER MATERIAL
PARTS LIST
UNFILLED CYLINDER
W-No.1.0338 EN 10139 DC04
CAP MATERAL
W-No. 1.0338 EN 10139 C03
0144
Ø18 +0.2
WASHER
0291
NO. SPEC 0198. E9421-99,0% PURITY N20 VIN
:
NOTES
1. INTERNAL SURFACE SHALL BE CLEAN, DRY AND
2. STORAGE TEMPERATURE LIMIT: MAX +50°C
FREE OF RUST AND/OR LOOSE PARTICLES
18T GmbH
ALL DRAWING DIMENSIONS IN mm
SCALE
AM IS GROUP COWPANY
2:1
STAR
01 302-07-10 n. Drg.
KPR
8g N20 / 10 ml ZYLINDER NIT BORDELKAPPE
L3sue Date Change Name
formation or dastriptiva matter not out BOUTEILLE DE 6 0 M2O / 10 ml A CAPUCHOW SEA
THIS DRAWING REPLACES
must not be diacioané loanad copied or vas
harain are castidentini aad enpyright a
0173
(ISSUE:
the owners
0173
ISSUE: 01
Proprietary & Confidential
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